So I think the minimum step you can take with the jog controls is 0.02mm. You can put a calibration card under Z and jog it so there’s friction, then set a custom increment of 0.02mm and jog up. If there’s no change in the fiction that’s the backlash.
A similar test can be done on X and Y with this: https://www.thingiverse.com/thing:2040624
However, that has adhesion problems and wasn’t super pleasant to print. Any more I use the laser and engrave a circle:
You can see as the compensation gets too much the circle has a jog. In person it’s easy to tell the .10 is too little, and .15 is too much. 0.1 ever so slightly has a left jog, 0.15 has a right jog. Since the right jog on .15 is much worse than the left jog on .10 I went with .11
You’ll notice there is no jog at the top and bottom of the circles - that’s with a Y correction of 0.02mm.