I want to use a pair of Xenar 135 lens cells with a RB Graflex Jr. (The 6.5" B&L Ic Junior came with is too long; closest focus is 10 feet). The Xenar cells came out of a No. 0 shutter which is now hosting a 150 G-Claron. Unfortunately, the G-Claron's aperture ring is limited to f/9. It is a modern-style barrel.

Does anyone have experience with this operation? The only way in I can see is the split ring marked in the pic. What is likely to happen if I take it off? I imagine there is a simple set screw somewhere limiting motion, but if the iris disassembles I'd never get it back together.