hmm, again i have to disagree, if its the first time you have fret dressed a guitar, i would def say do not use a stone. they take way to much off in one go. If its the first time then use a flat sanding block with 600 grade sandpaper, the sticky back kind is best as it will stay on the block. I learnt using a flat file, with the sharp end ground off, but you have to know for certain it is level and it cant be to rough, mill smooth is best.
have never liked usin a stone as i find it cumbersome, i prefer a small area tool, gives you more control. Also the frets need re crowning after you have leveled them, to ensure for accurate and smooth playability.