I've heard that too.. that you need a heavier spring to get the piston forward quicker or risk stripping, but I'm amazed your bearings stand up to that abuse. I left bearings in for about a season with a 400fps spring and they ended up blowing out...
As for the gear set, I don't have many more ideas. My cage is press-fit too but I swear I remember seeing a picture of one that was screwed together like Tys said.
Why not try making your own as a test piece. A bit of lexan the proper thickness, a scroll saw, files, teeth, what have you and have your own custom sector clip
Good luck bud...