Sounds good man and good luck. The stock gearing at 5.28FDR is meant for a 30T brushed motor or 17.5 brushless. So you can see why cogging may become and issue. For temps on you motor, you want to be under 170-180*F at the end of your run (Max Temps very a bit for each manufactor). Anything past that and you start demagnetizing the rotor. So basically it's safe to gear anywhere as long as your temps are in that range, lower the better of corse. If your racing, each race is usually 6 minutes long. Tuning tips I have learned for motor experts stat the following:
- Run car for 3 minutes. Temps should be no hotter then 130-140*F
- Run car for 4 minutes. Temps should be no hotter then 150*F
- Run car for 5 minutes. Temps should be no hotter then 160-165*F
- At the end of a 6 minute race. Temps should be lower then the max temp of motor. Usually around 165-180*F.
Again that is for racing. When your running the car for fun. Most of the time you run longer then 6 minutes. So basically you just never want to be above the max temp at the end of your run no matter how long it is.