setup info for my crt.5

Okay well i just picked one up. as of right now it has the extended jammin chassis, I will be running a a castle mm with a traxxas vxl motor. I have front rc8 threaded shocks coming to throw on the rear of it. I will also be installing a futaba 3305 servo for now till i can save up some money to get another hitec 7955 tg.

What size mod 1 pinion should i run to start off with.

What tires do most people like for the track with loose dirt. But also can get hard packed sometimes.