X-5 Gearing question

[myzislow]

Hi there, new X-5 owner here. I need a reccomendation for properly geraing my X-5. I belive the car is equipped with a 102t spur(it's white) and I will be using a Novak 6.5t brushless setup. The car will be ran outdoors on a well packed, semi-loose grip track. What size pinion would you reccomend? I am thinking 16t-18t but wanted to check with the experts first. I have a 19t laying around here, would that work or do you think that is too high? Thanks for any help you can offer.