Normally I only dabble in metal work (and only post on the Mercs forum as Vhe'dn Oyre), but I recently took a shot at building a vac table and came up with this, roughly cut out with minimal finishes:
Looking at the above picture, down the middle from top to bottom of the plates measures about 7 1/2 inches. Across the widest part of the chest over both plates, laid out like this, measures about 11 inches. I'd place these at a C/D cup size. Band size I'm a bit iffy about, but they're probably made to a small/medium frame.
My vactable set up, with an earlier failed version of a mold:
I'm very happy with how this second mold turned out.