suppllying a 3/4" thermostatic shower valve

[duckluver]

can I tap into 1/2" supply lines to supply a 3/4" thermostatic shower valve, or should I run 1" pex all the way back (25' or so) to the 3/4" copper pipes to supply the shower?

the shower demand with be one rain head, one hand held and two body sprayers.

Just found this set up...Is it adequate?

[h=1]Kohler K-DEV-BNDL-4-304-KS-BN Brushed Nickel Devonshire Complete Pressure Balancing Shower System with Rain Showerhead and Multi Function Handshower with Valves Included[/h]

 

[hj]

The actual water ports in a 3/4 valve are much less than 3'/4" in area. In fact, since they are usually two "pie shaped" openings the actual area is close to the same as a 1/2" pipe.