I have a couple of Rodagon lenses, kept them over the Componon-S lenses, no ral difference in actual use for B&W, but the Schneiders wouldn't allow my lens turret to rotate. I have the same problem with 50m El Nikkors. I could have used different mounting plates, but the 50mm wouldn't focus when I tried it on one. The 80mm Comp-S kept banging the rear cone even with the proper plate. If you could use a 25mm mount lens, I would recommend a Wollensak 90mm for your medium format, it was designed for 6x9and does a great job running a 6x6 neg up to 16x20 on my D-6 base, excellent corner to corner coverage, no fall-off.