Then you're going to have to change your gearing to match the track. If you need to get up to speed faster the shorter gearing will help, but if you find your self in mid-shift when you're leaving the face of a jump that's not going to turn out well.
The track will determine the gearing you need. If you ride on different tracks, you may need a different gearing setup for each. If you need more low end, go with your previous idea as a starting point and adjust as needed. Without knowing/riding/seeing the track you ride on, it will be difficult for anyone else to tell you exactly what you need.