I am looking for pinions for a couple of T-Rex 450s. One of them is a 450SE and the other is an XL. I have several motors and need help (1) identifying pinion sizes and (2) finding a place to purchase them. I would also appreciate some advice on recommended pinion sizes - keeping in mind I occasionally add a additional 10-11oz to the SE for Aerial Photography equipment!!! Here are the motors:
Align 420LF
Align 430L
Medusa MR-028-032-3400
AON "Vertical" V2815-3500 (I believe uses 3.2mm pinion)

Thank you for your assistance