So several tests of the original plan of using a friction-wheel to spin the dome suggested that while it would “work”, it was neither reliable nor consistent.
Matthias Wandel to the rescue!
Using Matthias’s gear template generator I spec’d out a ring gear for the dome ring, and a 9-tooth spur gear to drive it.
I split the ring gear into 45° sections, and cut the “master” by hand with a jigsaw. I then used the master to cut the rest on a router table with a flush trim bit.
Once all 8 sections were cut, they were glues and screwed in place on the dome ring.
The end result?