RonSA:
I'm using a 360 continuous servo pulling a timing belt attached to the camera carriage moving at the slowest the 360 servo could go.
CR servos are not known for precision speed control. I think your stepper motor idea should be an improvement over a CR servo but I also think a DC motor with an encoder would be a good match for this task. You could get a motor with an encoder on the motor which provides much better resolution than adding an encoder to the output shaft.
BTW, this is known as "hijacking" a thread. While your post was about motor speed, it wasn't really about POV displays. IMO, you would have been better off starting a new thread. Not that it matters much to me. Just a suggestion for next time.