The proper placement of the thin bearing, and why the retaining plates won't work.

I thought that the joint was supposed to be inserted all the way to the pivot's shoulder into the pelvic bracket. This is wrong. That would allow epoxy to contact the free spinning section and freeze the joint. This also illustrates why the metal pin needs the additional plastic for support. Had I mounted it as I thought, the joint and hip would not align. This is a critical step.