Well well well
I shot and proofed a screen for the MOSF show last night.
and after asking around I solved the exposure problem, it seems you have to sit on top of the board, kind of like the Dirt Palace's set up, except the AS220 shop's is taller and smaller. I hope i don't crack my head open.
I remember the old AS220 printshop, which was in the basement of the 115 Empire st building. We used full paint cans on top of foam. Very often you had to brush off roaches that were lurking on the foam. Ah memories.