Shower rough-in...how do I do this?.

(I posted this to the shower group...but maybe more appropriate here..)

Dear Group,
This is my first post. I have been searching for help and find you all w/ so much info I am hoping you can help.

I am building a master bath shower. The plumber is ready to "rough in" and wants me to decide on what shower system I desire.

What I want(i think) is:
#1: Overhead rainshower head
#2: Handheld on a wallbar
I also considered just a standard wall mount showerhead...but figure the handheld can serve that function...agree?

MY QUESTION:

I want to have separate control of VOLUME of each of these showerheads. I would like to have the rainshower running and be able to INDEPENDENTLY turn on the handshower *without* losing volume/pressure in the overhead rainhead. I would also like to have the temperature control separate of the volume control....

I am sooo CONFUSED about ways to accomplish this. I have read about thermostatic control valves that control the temperature...and then you buy separate volume control knobs for each head. I have read about combination valves(like MOENTROL?) where it is all in one...but it sounds like you would drop pressure/volume as you switch between heads?

What I am reading is that to maintain Volume/Pressure I want to bring 3/4" pipe to a rough in valve and then hopefully get 3/4" all the way to the showerheads?? Is that right?

Could you folks PLEASE outline *exactly* what product I need to buy(brand/model#). I don't care what brand/trim. I can find something I like in any brand. I would prefer if it was an all-in-one product that had temp/volume knobs all in one VS. having multiple knobs all over a wall..I just want to be able to tell the plumber what I need to accomplish this result.

Thank you so much,
DRK

shower

If you use a combination valve with a two way diverter, it will accomplish the usage pattern you want as long as the diverter has A, or B, or "A and B" options. BUT, the flow pressure may change because most of those valves have a limited capacity. A thermostatic only valve, such as Grohe or Hansgrohe, will have the capacity, but then you need separate volume controls. One advantage of this is that you only have to use one, (or two for both devices), valve to turn on the water. You do not have to turn on the faucet and then turn the diverter to the usage you desire.

hj said:

If you use a combination valve with a two way diverter, it will accomplish the usage pattern you want as long as the diverter has A, or B, or "A and B" options. BUT, the flow pressure may change because most of those valves have a limited capacity. A thermostatic only valve, such as Grohe or Hansgrohe, will have the capacity, but then you need separate volume controls. One advantage of this is that you only have to use one, (or two for both devices), valve to turn on the water. You do not have to turn on the faucet and then turn the diverter to the usage you desire.

Click to expand...

Plus you can set the temperature on the thermostatic valve and leave it, so that you won't have to fiddle with getting the temp just right everytime you shower.