Well, there is only one *really* small gear in a star wars yoke, and it is for the y axis. That is the one I replaced with an aluminum gear. The two gears for the X axis in the back are considerably larger. The gear I am talking about is the one that envelops the potentiometer shaft inside the front panel of the yoke.
I ordered my gear based on the info supplied in the rgvac note. That small gear on the Y axis (inside the front cover) is the one prone to breakage.
Good luck,
88mph