I shoot a 75 with the bag bellows on the Shen Hao. If I don't need much movement, I shoot the 75 with the standard bellows too. I believe that with the bag, you can use a 58 even with a flat lensboard. I would use a recessed board with anything super-wide like a 65, 58 or 47, and the bag bellows, just to insure that you get enough flexibility for movement of the standards. At those extremely short lengths, your rear element of the lens is literally a few milimeters from the ground glass, and the standards are hard against one another.