Unfortunately there is no universal answer to the gear up/down effect, espeically with brushless. I find that to a point, most like some amount of load and if under-geared, they seem to lose power everywhere. Best bet, if you have some time, try a tooth up and down, even if you can only test from cold for 3 minutes it should give you an idea of where you'll wind up.

Also, try turning down your current limiter. Start around 65%. I have never run mine higher than 80% on 4s.