IMO your question doesn't make a lot of sense...
Firstly your rollout or gear ratio will be determend by the track. Is it long and fast or short and nippy.
Secondly. Joe is right. Ask the fast guys! They'll know.
If I can recomend one thing. Get the Tamiya TB evo 5 90/96 spur geat set.
That allows good gearing for stock classes. OR Use the 102T 0.4 module Spur with pinions in the range of 31~34
That wont help much. So ask the fast guys