I've found that a 2" PVC (x2" tall) is less expensive....and more than adequate for painting jigs for personal use - and you don't have to use so much paint to get it going. Use stainless steel hemostats for holding jig to keep paint out of jig eyes. Brown paper bag generally works better than coffee filters, but laboratory filter paper is even better. Just the basic little aquarium pump from WalMart works fine. White powder paint will always make you cuss since it simply doesn't bubble up nicely like colors do (it's more dense/heavy). Glue your PVC coupling onto a piece of scrap wood instead of Lexan (too expensive). I got all my info from Cadman as well, but opted for the smaller cups.