Okay kids, this has gotten 100% out of hand. Having very slightly taller or shorter teeth on your pulleys will not affect the final drive ratio. If you have a 20 tooth main pulley, and 38 tooth diff pulleys, your ratio is 1.9. End of story. The ONLY possible advantage to having a slightly taller tooth of the same pitch would be to have it be a bit less likely to skip teeth. This is like how you could mix Mod 0.8 gears with 32 Pitch, where they were very slightly different one tooth on the spur moved one tooth on the pinion, same as how one tooth on the pulley moves the belt... one tooth! Which then moves the other pulley... ONE TOOTH!

This is getting too dumb for words. Stop measuring your pulleys with calipers and count the teeth.