Are you coordinated around tools and intelligent? I mean, you are on this forum, so it almost goes without saying.... For most of a decade now, I've been doing that sort of work with varying grits of wet/dry abrasive paper. No "file chatter", no file lines... a few whiles back, I did score an amazing assortment of gunsmith files off the bay -
http://www.ebay.com/itm/12-F-L-Grobet-SWISS-PATTERN-FILES-2-Nicholson-1-AM-Swiss-in-Heller-Tool-Case-/110975838656?_trksid=p2047675.l2557&ssPageName=STRK:MEWNX:IT&nma=true&si=Svl1Rnx3KWRVRuZzOE5%2BjhljM18%3D&orig_cvip=true&rt=nc
But I'd still end up with the paper. The coordinated & intelligent part has to do with A: being able to see what you are doing, which may take varying degrees of lighting and magnification; B: Dealing with the shrapnel, which in this case will be little tiny pieces of highly scratchy aluminum oxide that do an even better job on paint and lacquer than they do on fret ends. And as always, having a clear picture of the end result works better than just whaling away on it for a while. I can't imaging a fret end job that would need any coarser than 320 grit to start with. And before you start, write down all of the fret ends that need work, and which ones need a lot, and pick out a few fret ends that DON'T need work - these are your exemplars, to try to duplicate - the idea is to bang through the whole thing from start to finish without changing grits over and over (& over) for each single fret end. Use the 320 to get them all even, the 400 to smooth them - I would skip the 600, in this case - then the 1500, then ask yourself if you really need them to gleam immaculately, which can be done is several different ways.
I personally would use a shield and not tape off the neck, but you really need to be tracking your shrapnel intently for that sort of daring-do. And if you can't SEE the stuff - 10X, like - no tool can DO the stuff well. It may take a few hours, because you don't want to go fast until you've gauged the effect of each step - you may be surprised at how soft frets really are, in the face of sandpaper. But then, you're not it a hurry. If you are, you shouldn't be doing it in the first place. You have the whole rest of your life to NOT say "ouch!" every time you play that guitar...