Hi, Tony. I inherited a 65mm Cambo Wide from a friend who died, and I used it for the first time this weekend. I had made some shots in the back yard with old Polaroid print film, to test the coverage. I got some vignetting after about 1cm shift--of course, there's a white border around the Polaroid print, so it didn't show everything. Then this weekend I shot some regular sheet film in Grafmatic holders, and I found the vignetting to be severe when using the shift. I can see the whole arc across the top of the frame, not just at the edges, and I used f32. I'd say be careful at full shift with the 6x12--don't count on covering the corners, and make some test shots. The published specification on the lens is a 170mm circle at f22, and I would guess the diagonal of your film area will be about 130mm, so you should have some room. On 4x5, you need about 160mm, so this is really a straight-on camera with full sheet film. With 6x9 there would be no problem at all, and I think that's really the format that the camera's movements are designed for. I noticed on my screen that there are makings for 6x6, 6x7, and 6x9, but not 6x12. There could be a zillion reasons for that. The image on the groundglass, if you have the Fresnel screen, is nice and bright, and the camera is generally easy to use horizontally--I found it somewhat awkward flopped over for verticals (on a tripod in both cases). Good luck with yours!
