Controls and Diverters
This may be almost impossible to thoroughly attack because there are so many variations in what people want and in what different manufacturers offer.

In general…

You need a volume and temperature control. You can buy just the valve body, which is the chunk of expensive brass that gets buried in the wall, and buy a separate trim kit, or you can buy a package that includes the valve body and the trim kit. The trim kit is the bright sparkly metallic knob/lever/escutcheon bling that you overspend for so your friends and neighbors will go "oooooh" and "aaaaah".

If you buy a pressure balanced valve, the valve in and of itself will turn on the water and allow you to control the temperature. If you buy a thermostatic valve, most valve bodies have two controllers on them, one to control volume and one to control temperature. Read the fine print though, because some thermostatic bodies just control temperature. You’ll need a separate valve body to provide volume control.

Stops. Some valves come with "stops" some do not. What are stops? Stops stop water flow at the valve itself so the valve can be taken apart without having to turn the water off to that branch circuit or to the whole house. They are normally incorporated onto the hot and cold water inlets on the valve body, and they can be opened or closed with a screw driver.

While I’m on this, I’ll also mention that some valves might mention having a "stop screw" to limit the maximum temperature. While a pressure balancing or a thermostatic valve will prevent you from being scalded if someone flushes a toilet, there is nothing to prevent someone from being scalded by setting the valve to allow 130 degree water to pass through it. Your first step is to lower the temperature on your water heater to about 120 degrees. For valves that have these stop screws, it’s then a simple matter of setting a screw that limits how far the temperature knob can be rotated. What you do is rotate the knob to set the water to the max temp that you’d ever want out of the shower, then you turn the set screw until it bottoms out. It will now prevent the temperature knob from turning past (hotter than) it’s existing position.

Downstream of that volume/temp control is where things get dicey. You can have a simple setup where your V/T control just runs to a single shower head. Easy to do. You can have a standard tub setup with a shower head and a tub spigot, where the diverter can be a lever or push button that sends water either to the tub spigot below or to the shower head above. Also easy to do.

If you want to supply water to more than one shower head, to a shower head and body sprays, or to both, either simultaneously or one at a time, then you’ll need more chunks of expensive brass to bury in your wall.

If you want separate controls and the ability to have differing temperatures come out of differing fixtures, then it’s easiest to go with multiple V/T controllers. One V/T controller for the shower heads, for example, and a separate V/T controller for the body sprays. This allows you to run different volumes and different temperatures out of the different heads. Your shower head can be 105 degrees and your body sprays 110 degrees.

Remember, the more hot water that you want to come out of your shower, the larger your supply tubing and valve bodies need to be, and the larger your water heater has to be. For sizing purposes, most shower heads and body sprays have a gallon per minute rating applied to them. In theory and planning only, if your hand held shower head is, for example, rated at 3gpm, your rain shower head rated at 4gpm, and each of your 8 body spray heads is rated at 1gpm, and you want to run them all at the same time…you’re looking at a flow of 15gpm. You need a water heater that can supply you with 15gpm of hot water, then you need supply tubing that can get 15gpm of hot water from your water heater to your bathroom, and you need valve/diverter bodies that can pass the required amount of water through them so you get decent flow out of each fixture.

Typical plumbing is 1/2", typical valves are 1/2". For high volume situations, 3/4" tubing and 3/4" supply valves may be required. Out of the valves you can usually run 1/2" tubing to your shower heads and body spray heads.

Back to the hardware. If you want a shower head and body sprays, and want to run either or both off of one valve, then you’ll want a diverter valve.

Diverter valves can be anything and everything. They can be simple A/B valves, where you can run the water through the valve to only "A", your shower head, or only to "B", your body spray heads. But not both at the same time.

Which leads to the A/B/AB valve, where you can send water only to "A", your shower head, or only to "B", your body spray heads, or to "AB", simultaneously to both.

And from here things go wild. There are A/B/C/AB/AC/BC/ABC valves, and things just can go on and on from there.

Diverter valves are usually described as having a certain number of "ports". 3-port, 4-port, 5-port, etc. Realize that one port is where the water goes in to the valve, the other ports are where the water comes out. So an A/B/C valve that has three outlets might be listed as a "4-port valve", with the fourth port being the inlet.

Not all 4-port valves can do A/B/C/AB/AC/BC/ABC, you’ll need to look through the description to find out where it can send the water to. A 4-port valve might just be an A/B/C valve, or it might be a more versatile A/B/C/AB/AC/BC valve. Read its description.

If you can’t get the customization you need from a single volume/temperature controller and a single diverter, you can run multiple diverters off of one V/T controller, or multiple diverters off of multiple V/T controllers. It all depends on how much brass you can afford, how much water you can supply, and if you have the space to hide all that brass in your walls.

Diverters can be knobs, levers, push buttons, the choice is yours. But do remember that you need to match up the valve body to the desired trim kit so that the bling that your neighbors can see will fit on the expensive chunk of brass that they can’t see. You don’t want your plumber to bury that expensive chunk of brass in your wall, then tile, then find out later that your bling won’t fit. Very depressing.

It’s all about reading the fine print.

Mongo

The sort of where, what, and why of pressure-balanced versus thermostatic:
Pressure-balanced or thermostatic temperature control valves are code-required in bathroom plumbing because they eliminate potential scalding and cold water shocks that can occur in a shower.

If you are using the shower and a toilet is flushed, as the toilet uses cold water to refill the tank, the pressure in the cold water line drops a bit below what it was when just the shower was running. If you had a non-balancing valve, you’d still get the same amount of hot water that you originally were getting, but with the drop in pressure in the cold water line you’d have less cold water coming out of your shower head, creating a potential for scalding. Vice-versa, if someone turns on a hot-water faucet elsewhere in the house, the hot water pressure drops and you get a shower of mostly cold water.

A pressure-balanced shower valve is designed to compensate for changes in water pressure. It has a mechanism inside that moves with a change in water pressure to immediately balance the pressure of the hot- and cold-water inputs. These valves keep water temperature within a couple degrees of the initial setting. They do it by reducing water flow through either the hot or cold supply as needed. Because pressure balanced valves control the temp by reducing the flow of water through the valve, if your plumbing supply is already struggling to keep up with the three shower heads and nine body sprays that you have running in your shower, if a pressure balancing valve kicks in and chokes down the water supply to keep you from getting scalded you could end up with insufficient water flow out of the heads in a multiple shower head setup. When it comes to volume control, in terms of being able to turn on the water a little or a lot, for the most part pressure-balanced valves are full-on when water is flowing or full-off when the valve is closed. Flow-wise, think of them as having no middle ground.

Where flow and volume control are important, as in a shower that requires a high volume of water, a thermostatic valve may be the better choice. They also control the temperature, but they do not reduce the amount of water flowing through the valve in doing so. Thermostatic valves are also common with 3/4" inlets and outlets, so they can pass more water through the valve than a 1/2" pressure balancing valve.

Which should you choose?
In a larger multi-outlet master shower, while a 1/2" thermostatic valve may suffice, a 3/4" thermostatic valve might be the better choice. But it does depend on the design of your shower and the volume of water that can be passed through your houses supply lines. In a secondary bathroom, or in a basic master where you have only one head, or the common shower head/tub spout diverter valve, a 1/2" pressure balancing valve would be fine.

If you want individual control and wanted multiple valves controlling multiple heads, then you could use multiple 1/2" valves instead of one 3/4" valve and all would be just fine.

What do the controls on the valve actually control?
While it may vary, a pressure balanced valve is normally an "all in one" valve with only one thing you can adjust…the temperature. The valve usually just has one rotating control (lever or knob) where you turn the water on, and by rotating it you set the water to a certain temperature. Each time you turn the valve on you’ll have to set it to the same spot to set it to your desired temperature. For the most part you really don’t control the volume, just the temperature. With the valve spun a little bit, you'll get 100% flow but it will be all cold water. With the valve spun all the way, you’ll get 100% flow, but it will be all hot water. Somewhere int eh middle you’ll find that Goldilocks "just right" temperature, and it’ll be at…you guessed it…100% flow. So with a pressure balancing valve, you control the temp, but when the valve is open, it’s open.

A thermostatic valve can be all inclusive in terms of control (volume and temp) or just be temperature controlling. If it’s just temperature controlling, you will need a separate control for volume or flow. Example, with an all inclusive you’ll have two "controllers" (knobs or levers) on the valve, one to set the temperature and a separate one to set the volume. In this case you can set the temp as you like it, then use the volume control lever to have just a trickle of Goldilocks water come out of the valve, or you can open it up and have full flow of Goldilocks water coming out of the valve. You can leave the temp where you like it when you turn the volume off after you’re done showering. The next time you shower, turn the volume on, the temperature is already set. Some thermostatic valves are just temperature valves with no volume control. You’ll need another valve/control to set the volume. Read the product description carefully to see what you're getting.

What size valve should I get?
Yes, valves actually come in different sizes. The size refers to the size of the inlet/outlet nipples on the valve. For a basic shower, a 1/2" valve will suffice. For a larger multi-head arrangement, a 3/4" valve would be better. Realize that you’ll need a water heater that can supply the volume of heated water you want coming out of the heads, so don’t forget that when you build or remodel. Also realize that if you’re remodeling and have 1/2" copper running to your shower, capping 1/2" copper supply tubing with a 3/4" valve provide you with much benefit as the 1/2" tubing is the limiting factor. You can, however, cap 3/4" supply tubing with a 1/2" valve or a 3/4" valve.

Is one better than another?
Thermostatic valves are "better" in that with them you can control both volume of flow and temperature, so you have more control, and they hold the temperature to a closer standard (+/- 1 degree). They also perform better if you are running multiple outlets in the shower, as they do not choke down the amount of water in order to control the temperature. But you pay for that added flow and added control. Pressure balancing valves can be had for about $100-$200, thermostatic valves can be twice that amount. And more.

Will I suffer with a pressure-balancing valve?
For what it’s worth, when I built my house over 10 years ago I put pressure-balancing valves in my own house. While I have two outlets in my shower (sliding bar mounted hand-held on the wall and an overhead 12" rain shower head on the ceiling), I have a two separate pressure-balancing valves, one valve for each head. With both heads going in the shower, I notice no loss of flow in the shower when the toilet is flushed and the sink faucet is turned on simultaneously. I also notice no change in temperature. So they work for me.

If you are remodeling, if you have your existing sink running and you flush the toilet and notice a drop in volume coming out of the sink, then a thermostatic valve might be the better choice even if you're not having a multi-head setup installed.

If, as part of the remodel, you plan on running new supply lines through your house to the new bath, then properly sized runs will take care of that flow restriction and you can probably do a pressure balancing valve instead of a thermostatic.

So in a house with tricky plumbing, or with a restricted water supply, or with multiple outlets running off of one supply valve, a thermostatic valve might be the safer choice.

Mongo

Like:
-deep storage drawers in the vanity. A happy accident. All the tall stuff fits in them!
-double curved shower curtain rod, we wanted it to hang our towels on the inside rod. Works great. (only about $60 at BBB, Moen)
- Moen shower curtain hooks. They have roller balls for easy use and we got the ones shaped like a U with each end curved up. It holds the liner on the inner, longer side and the curtain on the outter, shorter side so the liner doesn't show, and it allows the liner more overlap of the tub wall. (about $15-20 at BBB)
-changed the vent fan to a fan/light combo, ultra quiet model
-switched out the vent control from a standard light switch to a timer that fits in the same space (maybe $30 or so at Lowes)
-set floor tile at an angle
-towel/robe hook next to shower, use it every day and it's so convenient
-comfort/chair height toilet with easy off seat and soft close hinges. The easy off seats make it sooooo much easier to clean!
-framed mirror
-higher vanity counter, much easier to use, though it was also a happy accident
-matching satin nickel tub drain and stopper toggle, which I found by accident after it was all done and swapped out myself. Never knew they came in different finishes, now everything matches!
-memory foam bathmat from BBB, it's like stepping on a cloud when getting out of the shower!

Would do different
-wish I had had the extra electrical run to operate the vent fan and light separate and the night light
-would have thought more about what to do where tiles meets the baseboard and the threshold to the hall
-would have recessed the medicine cabinet. So much is now in the vanity (and it's the absolute worst place in any home for meds) that a smaller one in the wall would have looked nice.
-backsplash along wall at the left of the vanity
-inspected the walls better before paint went up. The paint is the only thing that actually bothers me, the backsplash does a little when I clean, but not much.

I'm pretty happy overall, not bad for about one week notice. Should be able to see most, if not all, of these in the pics below.

To the right of my refrigerator is an oversized walk-in pantry. There are temporary shelves in there now... someday soon we'll have cabinets and nice shelving and I'll share those pics as well :)

The blue represents the size of the standard shower in our old house. The total space taken up by the shower is about 7' x 5.5'

My husband is an engineer and very concerned with "modifying" structures of any kind for fear of weakening or lowering their strength. He did end up cutting out a portion of the sink base (see pics below) and feels that the sink base is still very sound/sturdy.

In the picture below, the left side of the sink base has been cut "notched out".

Then, we notched out the right side

Now, the 30" sink fits into the 30" cabinet

Here is a link that might be useful: Almost Finished Alder, Silestone and Granite Kitchen

Parts List
1. In wall wiring - Ideal brand low voltage wiring (from HD or Lowes).
2. Ideal Plug disconnects (from HD or Lowes).
3. Lights - depends on how much light you want, total length of cabinets.
4. Transformer(s) - depends on cummulative consumption + 15% margin.
5. Inter-connect wiring.
6. Lightbars from http://stores.ebay.com/LEDpro-Lighting Email sales@photonier.com for pricing sheet.
7. Transformer from environmentallights.com
8. Leviton 6613 magnetic dimmers – 1 for each circuit/zone. Check with transformer supplier if you’d like to use a different one. Incompatible dimmer switches can void your transformer warranty. This particular dimmer reco assumes that low voltage (12V or 24V) LED lighting will be installed and contains many details specific to environmentallights type lightbars. Magnetic dimmers from various vendors could be used, but require some testing first. If you use a different transformer, check with the manufacutuer if there are known problems with certain dimmers. You can Hook up the system prior to installation for a test run if possible - switch(es).Things to look out for
1. There is no buzzing/ humming sound from the transformer when everything is hooked up and powered on.
2. All lights are equally bright, especially at the ends.
3. No flickering
4. No problems when dimming.

Tips specifics to this type of environmental lights type lightbar:
1. It’s a waste to buy the long length 3 prong interconnects. Just cut the interconnect wires and attach to a disconnect.
2. Two adjacent prongs are actually connected to the same DC line. The third is connected to the other DC line.
3. The right angle interconnects are probably more useful for connecting bars set at an angle to each other.
4. You could use flat wire under the cabinets as it comes with double side sticky tape. Some DIY work would be necessary with a soldering iron + heat shrink tubing.
http://www.flatwirestore.com/mm5/merchant.mvc
The flat wire is useful in situations where you do not like to see standard low voltage wiring.
5. The plug disconnects would be used to connect the in-wall low voltage wiring to the lighting power cords which connect the lights. It would also connect the in-wall low voltage wiring to the transformer. This way, if you ever decide to change out all the lighting bars to another make, it would be a simple matter of disconnecting from the plug disconnects and perhaps the transformer.

Thanks to davidtay for this information! Be sure to watch both parts of the DIY video below. It’s shows how to wire these to household current.

Here is a link that might be useful: UCL Install Video

-How many pucks or light strips should I add?
-How many pucks or light strips should be in the 30" wide frosted glass cabinet above the microwave?

Thank you so much.