It looks like the lens Chris is offering is a very good option for me right now; I am looking for lens boards and it appears all KEH has in stock are recessed lens boards like the one I have, assuming the lens is a Copal 0 (Chris said the mounting flange is 1.5 inches).

If it's a Copal 1, they have the boards in stock but they're $35 in BGN.

Any other sources for lens boards? Can I use another manufacturer's boards for the Calumet?