Chris,
hi fellow Garlitz geodome owner
I'm interested in your outcome as I'm in the same situation.
I'm ready to convert the base-ring to a 360 degree drive and have it
synchronised to the Bartel drive via it's interface.
The spanner in the works is finding a suitable mechanical drive that
will not slip
I have two identical motor/gearboxes ready for the
job to share half of the load each side of the dome.
Barry from Canberra might have some suggestions.(bloodhound on IIS)
I believe his is still manual but he has been through a few prototype
designs and is happy with his present drive idea, last time I checked.
Steve