I'm doing a partial master bath remodel and plan to use PEX for part of the piping. Installing a large whirlpool tub and a walk-in shower with two rain heads, hand shower and six body shower jets. All of which can be used alone or in any combination. I doubt the shower and tub fill will ever be on together.

My current water supply into the bathroom is 1/2" CPVC (southern home, built in late 90's, typical piping for us). My question is should I go with 1/2" PEX which has a ID slightly smaller then the CPVC or 3/4" PEX which has a significantly larger than the CPVC. I'm worried the 1/2 PEX won't flow enough water for all the shower jets and I know the wife will definitely be trying it! Pipe will be PEX "B", "A" is very seldom used around here and I already have a crimper for B.

Thoughts? Thanks!