Do the math... go from 200 steps to 1660 steps means just over 1:8.
Turntables like that would have to rotate at no more than 2-3 rpm, which is already way faster than real life.
A typical stepper can easily reach 1000 rpm, likely double that. You can use 1:500 gearing on that.
For your project, 1:100 sounds good. Easy to get when you run the thing from the edge as suggested before.
Considering these speeds and the light duty of an HO size turntable, the venerable 28BYJ-48 stepper should be considered. It's really small, makes 2048 steps per revolution, maximum about 30 rpm but that's pushing it, up to 20 rpm is no problem. Those little things would be a good choice in combination with a 1:3-1:5 gearing ratio.