On the KMG grinder both the drive wheel and tracking wheels are crowned. That does seem to help rather than having only one wheel crowned. I started with only the drive wheel crowned and tracking was more sensitive, and while some belts tracked with no wobble, some did have a bit of wobble. I crowned the tracking wheel also, and now the grinder really tracks nicely. An easy test is to wrap some tape around center of the tracking wheel or the drive wheel (or both) to add some crown and see if that helps the belts track with no wobble. Of course, the tension arm MUST be aligned.
Good luck, Ken H>