Your build - your customer.... Not saying you shouldn't do whatever you feel like doing. Just saying that power brakes shouldn't do anything for you except to be able to run the pedal with your little toe instead of your big one.
I would find that my feet are way too busy to be trying to modulate a power brake let alone trying to trail brake one... but it's not my car. If I was only going to drive it on the street -- and I wanted a girl to drive it... then I'd put power on it. LOL