[nuz69]

Well, bigger pinion on bigger motor means nothing in terms of "extra gearing".
The longer motor produce more torque for the same current, so geared for the same speed the current will be theoritically the same.
In the reality, the current will be a little smaller in the longer motor, as it's run more efficient (less magnetic losses as it spins slower, less heat as it handle the same power in a longer can...).
But this is true if the widings are the same, which the case between all of thoses motors (1 turn star widings).
So don't be worry using bigger pinions on longer motor ;)