on the kronos the higher the number the harder the compound. for handling you should have a softer tire in the rear, for drifting do the opposite. the trick with drifting a 2wd r/c is you don't want to go with the hardest tire possible in the back cause the car will just go in circles. you want a hard enough tire that its not getting the best traction, but you need something that will have some bite to keep in controlled. being you have a selection of tires try some different combos out. whatever you end up doing, don't expect a pair of tires to last more than a tank of fuel.
as for gearing, id stick with stock. you need some wheel speed to get it sliding properly, the 20/44 will break the tires loose very easy but the thing is going to top out real quick and you wont have any wheelspeed.
