OK the quote to have 8 variable sized masks cut out of 304 grade Stainless steel will cost $192.50 making them on average $24.06 each for this batch. Obviously the larger ones would be dearer normally. I think this is excellent value for money - and an economical way of getting a decent focus mask. Many thanks to Dennis for his help and the input of everyone who posted advice. and see post 197 for the CAD dxf file
I have ordered them and will have them next week - enough time to spray one side matt black and add felt to it before IISAC.