Increasing the riser pipe to the rain head for max flow

[Hammer]

I was told that to provide sufficient water flow to a rain head when operating 2 functions (rain head and body spray) at the same time I would need to increase the riser pipe to the rain head for max flow.

True?

The valve has 1/2" inlets and outlets and if made to operate (2) functions at the same time.

Confused.

 

[Mr_David]

It may help some. A bigger factor is the pressure behind it.
Even though The valve has 1/2” supplies, the ports inside the valve are smaller. Sometimes only maybe 3/8”. If you have really good water pressure can improve flow and an increased pipe can add volume