Trial and error is probably what will satisfy each individual case.
From my experience, I have not used residual valves. I have a '54 3800 Chevy panel truck that I put Power brakes in 23 years ago, no residual valves. The booster and Master are located in the orginal under floor location. The truck stops on a dime and the pedal feel is excellent, like a brand new truck.
I have a '54 3800 Chevy rack body that put the Corvette master in with the residual valves, and had a very hard pedal and stopping power was poor. And , no I didn't have the residual valves in backwards. I actually tried 3 different sets of residual valves from different manufacture and they ALL were poor.....so I removed the residual valves and the pedal feel is great and the truck stops on a dime. So, I have not had any residual valves in this truck for 6 or 7 years now and it is a daily driver. Try what you feel will give you the best result.
You can always add the valves or remove the valves depending on your braking ability. Safety first !
