With the platform rotating with very little friction, the stepper is the next thing on the list. Because of their insanely low pricetag and the tiny step size I opted for an 28byj-48.

I used a handheld router to remove a round shape around the race on the upper part of the platform.

After sanding the remaining area and printing a wheel for the stepper tomorrow's task will be to mount the motor in the lower half of the turntable, improvise some suitable belt and test the contraption.