Most of the nuts came out with minimal force, but the last one just spins in place. I tried rubber gloves, painter's tape, and duct tape to get a better grip. I'd rather not cut a slot in the domed nut if there's another good strategy.
The rest of the restoration underway:
@pageflight
The best way to handle this is by clamping the side that doesn’t take a driver.
Bob Rozaieski used to have a good vid on this, which seems offline now. But here is a similar idea.
https://youtu.be/xE0yh4tV1WI
How do you clamp a bolt head that's recessed?