I hope this picture explains the concept. Since I don't have real bearing blocks, the bearing pair is pretty much free to self-center when the Y-plate is moved close. They have about 1/10" latitude to move to either side. If the friction turns out not to be sufficient to hold them in place while operating on the other side, I can put a bead of silicone around the outer race. I know, also a bit unconventional and I don't expect all my ideas to work perfectly