the flange distance of the 58mm Schneider is 77mm. Thus, one would have suspected that the lens would be fully "useable".
Have you ever felt restricted in your inability to use longer lenses?
Edwin
Edwin, if the ffd is 77 mm then you may well be fine with a flat board. I was working from the Super-Angulon XL 58/5.6 datasheet that I have, which gives the ffd of this lens as 69.3 mm. It is possible that the lens you have is not an XL, or whatever, and if the ffd is indeed different, then I would not buy a sunk panel in the first instance without trying the lens on a flat board first.
The longest lens that I use on a regular basis is a 240 mm, but then again I use this camera mainly for roll film, not 5x4. I have a 300 mm lens mounted on an extension panel, which works just fine too. I have not tried anything longer on this camera.
I find that it's one of the easiest cameras ever to use! Very rapid to set up, easy to operate, etc. You have to remember to zero the front standard before bringing the standards together at the end of a session, otherwise you will squish the bellows off the default folds, and they may end up not as pretty. Easy to forget to do if it starts raining, or if the wife was expecting you back at the car 20 min earlier
George