Steve, I'm not sure that you have to limit yourself to an ancient vintage shutter. A relatively modern vintage shutter might do.
You say your lens will fit into a hole bored for a Copal #1. This means that its diameter at the rear is no more than 42 mm. With the help of a threaded bushing it should fit into the front of an Ilex #3 (~45 mm according to http://www.skgrimes.com/library/used...-shutters/ilex).
The big question with front-mounting a wide angle lens is mechanical vignetting by the shutter. At present the shortest lens I have front mounted is a 60/14 Perigraphe that fits an Ilex 3 (odd coincidence, eh?). Vignetting is indeed a problem with it, even with the shutter's rear tube truncated the lens covers only around 90 degrees, but that happens because the lens sits so far in front of the shutter's aperture. Read about it at http://www.galerie-photo.com/telecha...2011-03-29.pdf . There are pictures.
I think your lens will go much deeper into the shutter than my 60/14, which sits entirely in front of the shutter, and of course your lens is longer so it shouldn't lose much, if any, coverage to vignetting by an Ilex 3's rear tube. If it comes to that, the shutter's rear tube can always be truncated. Read my lens diary, you'll see that how a shutter with no rear tube can be attached to a board.
FWIW, I'm just about convinced myself to send a 45/9 CZJ Goerz Dagor to the machine shop to have an adapter that will hold it in a #1 (not possible with a lens as large as yours). The trick there, and for your lens, is to have the lens set as deep as possible in the front of the shutter.
Ian, I don't mean to dump on you, but in my experience ancient constraints don't always bind.