I do not know what Intake system to use because the piston launcher is what my teammate are gonna do.
A piston ball intake might be hard to pull off as you still need some way to transfer the ball onto the launcher (or, I'm assuming, puncher). Perhaps a roller intake might be better? A single 393 motor is sufficient to power a roller intake and a belt system to load the ball onto the launcher.
I really enjoy the intake system 118 used for nothing but net:
Although it is a catapult, I think it would be just as easy to make it work for piston launchers as well. And if you find those side rollers to be a bit more complicated, you can make a rubber band ball intake.
EDIT//: Oof I tried to press enter but it posted instead