I think you'll need to do the math on the tooth counts and work backward from the fact that the clear disc rotates one time per hour. And your number will be best expressed as "RPH" and not "RPM".
i.e.: If the main disc has 120 'teeth' and the motor wheel has 12, the RPH would be 10. If the motor wheel has 10, the RPH would be 12.
In one of the previous discussions about this, someone said the number of links in the ball chain would be a factor, as well.
Except for where the disc hangs in space... It isn't a factor.