I now have a cordless blower (cost arount $60) which clears things pretty quickly. With my Sprint 2 i never had any problems with the belts but would get pebbles stuck in the spur gear, so i made a little cover out of a plastic cup which helped alot. I see alot of people running their belted cars on the street and then complain that the manufacturer made a crap car because it tears up belts like no ones business.
In regard to which pinion gear to use, my sprint2 used a 23 pinion and 90 spur with a internal gear ratio of 2.13 so 8.33 and XI would be 23/87*2=7.56 so i think things will be ok. I will just keep an eye that nothing gets too hot and adjust gears to get the speeds i need.