i just use whatever grit i can find but i noticed that 100-300 grit ive liked the best but nothing over 600 grit i would recommend because that's a little to fine to do this.
tire bands are a great investment
i for sure like em better then holding my tires or using tape like i used too
these are cheap and you get 8 of them
http://www3.towerhobbies.com/cgi-bin...?&I=LXXSK6&P=7