I ran one 3/4" hot pex line to the master bathroom which serves a manifold that branches into five 1/2" pex lines. There are 3 fixtures plus 2 shower heads on pressure balancing valves. I don't want to have a pressure drop if both shower heads are going and someone turns on the hot water in the sink, for example. Should I run a separate 3/4" pex hot line that is just dedicated to the master shower? Is that necessary?