The stock spur on a T1 is a 93 tooth 48 pitch. As for what pinion to use, I have no idea for that track.
Last winter I was running a 28 to 30 tooth depending on rollout, and now I'm runing a 21 at a different track.... which that information probably won't help you in the slightest.
For tires I (accidently, ordered the wrong part numbers) ran 24 mm Jaco foams for a while, then changed to 28 and it was a huge difference. Considering the price is the same and such, theres no reason that I know of to run the 24s over 28 mm tires.