Thanks for the input guys, very good information here. If I'm understanding the ball valves correctly, they are tied to a specific area of the vacuum table, so if you don't need vacuum there you turn off the valve and I imagine you get even better vacuum holding power in the rest of the zones. I like that concept (if I'm correct in understanding it).

Lambodesigns--I appreciate your detailed feeds/speeds. Very good baseline for comparing what I'm doing. Now if I'm understanding you correctly, you are saying a small part is roughly 1 square inch?? That is tiny!! I'm trying to think of my smallest part, and I'd have to say my smallest is between 5-10 square inches. If I need to add tabs for some of the small parts I'm OK with that. It would be really cool to have some kind of vacuum holding for at least the bigger parts.

At what point, with the shop vac, did you find parts starting to move on you?