If I read this tread correctly, This is what I got out of this.
Scott asked about how to get more power at the end of the flight. Assuming everything else stays the same, a Throttle Tech will do that, at the cost of power at the beginning of the flight.
Changing the C rating will give you a higher voltage through out the flight resulting in a higher RPM. (Power will therefore be higher as described by the equations provided by others above)
Changing the mah rating will help also by slowing the rate that the voltage drops off. Thus having a higher voltage at the end of the flight.
Summary:
Each of the above solutions will work. But each has their own trade off's
Increasing C rating and mah's will both result in higher weights that will consume some of the increases you are achieving.
The Throttle Tech will cost him power at the beginning of the flight.
Did I miss anything??