gear ratio;s

[BrianG]

What ESC are you planning to run? I heard the MM can run multi-pole motors, but 12 might be too much. The Quark 125, for instance, has special settings for outrunners.

As far as gearing: Outrunners are known for having higher torque ratings. So, you can gear higher than you would an inrunner. If you have the spurs/pinions, I would start at a typical inrunner gearing (maybe higher to account for the reduced overall rpm) and then go up from there.