Tape off the board, go along the direction of the fret with grit 600, 1200, 1500, 2000, then a metal polish compound, then another rubbing compound. I'm done within 20 minutes. Taping takes 5 minutes, leveling often 10, then crowning, another 10 to 15. All in all, I'm done with a level job within an hour.
I use a dremel with a felt wheel, and Menzerna 'pink' P126. I'm looking for another compound that will cut more aggressive the first pass, and then a compound for the second pass. I used to use a liquidy gelly kind of gloop but that stuff gets EVERYWHERRREEEEE so I want to phase that stuff out.