Have just finished a Belt drive CGE conversion which is working but I believe missing the target when slewing, not by much but enough. Here are my numbers from the config utility.
I am using Ramps with a TMC 2208 with all links in which should give 16 usteps interpolated to 256.
The Worm has 180 teeth
The stepper cog has 17 teeth
The Worm cog has 16 teeth.
The Stepper has 1.8 deg steps
My settings in the utility are
Motor steps 1.8
Motor gear 1.0625
Worm 180
Usteps disabled
16 Usteps
Results
Axis steps per rev 612000
Worm steps/rev 3400
Sidereal IRQ 6364
Siderial speed 896
Resoloution 2.118
Can you take a look and see if I am messing up somewhere. The mount slews fine and will track, not sure how good that is yet, but comparing it with my Atlas when slewed to the same object it's out about the same in both axis.