Nice job with the graphics. Excellent point when you said,
Also note: the correct gear angle is to the contact spot on the scale – not necessarily the leg itself.
You could add a dashed line from the point of tire contact extending up to
the crank center line and extend angle a to that line. The drawing would than apply to either geometry, making it clear that the load path through the gear is irrelevant
Better yet, get back to building.