Not sure what the diameter of the ball is, but I have 7 gallon Fermonsters, so I went with a ball that had 1" NPT threads to minimize the reductions off the pump. You can get smaller ones though that may fit through a sanke or standard carboy if that's what your thinking.
I cleaned 3 carboys tonight, and it hits them perfectly at the krausen ring. I'm really happy with it.
I thought about foregoing two of the valves, but every time I've done that in the past, no matter the plumbing project, I've kicked myself. It didn't add that much to the overall project, which ended up just under what I've seen the Mark keg cleaner sell for. I think this will do a better job and be more versital for me. I'll be able to clean 4 keg lines at once with my Intertap ball lock tips and the ball lock x ball lock unions I already own.