Alrighty :)

Found a link for a shaft extender that will work..

But as far as the pinion..what would be a ideal number of teeth? spur gear is a 39t.

would 19/39 sound alright? (5700kv 4 pole castle system)

Planning to use a 2200mah 2s 45c lipo..also..would that provide enough amps to the system? If not..I can run to in parallel..can only fit a 100m long battery in the limited space..width is about a little less then 100m..