I have stepped from a 7 turn orion to a brushless system now. a Mamba 5700. what would be a good starting point for the spur/pinion combo. the track has medium grip and the stright is 250 ft long with a technical infield similar to the track at the 2006 IFMAR worlds, many hairpins and hairpins at the end of the striaght in either direction. i guess i wold have to gear it high, so where would that be?