Angular or axial misalignment?
Sounds like axial to me. The thing you are calling a radial gear is called the cervic coupling. When the turret indexes it moves out a little and then pulls back and the coupling engages and that is what locks the final alignment.
If you have angular misalignment, fix that first.
My Nakamura had taper pull pins for alignment. The idea is the pin holes are reamed when the machine is built, but the pins are removed after the screws are tightened. Then after a crash, loosen the screws, drive in the pins restoring the alignment, tighten the screws and remove the pins.
All too often after a crash, the pins are left in and the next crash wallows the pin holes rendering them useless.
All I can suggest is to remove the pins from one or both rings, snug the screws enough to hold the couplings, assemble the thing and bump the turret until aligned. Then take it apart and tighten the screws. Reassemble and inspect. This will be a trial and error and it may take all day. Good Luck!