Usually you can.
All copal 0 can be mount in all other shutters with size 0 and in the any way all schneider-rollei lenses can be mounter in copal 0 shutter.
This is the fact.
The other story is about getting the same optical quality with different shutters, no matter if other rollei-schneider or other copal shutter. No shutter have exactly the same size then the other, 2 different copal shutter have two different sizes and the same with rollei-schneider shutters. The small rings compensate the tolerance between the different shutters. But it does not mean than when one copal shutter need one ring that the othe one need it two. When you have the knowlege you can calibrate your lenses for best optical quality that the lens can acheave. When you cant Schneider do it for 150 euro.Also Rodenstock- but not with HR lenses!
This is different story! I was talking about it with mr Wenzel from rodenstock, these lenses are really complicated made and the shutter is a part of the optical calculation.