It is, if you have a lot of time available and are really careful and lay down everything in paper before the actual job. The hard part is making the neck having the exact relief as the intented future style-setup, or at least having it str8. I have done this 2 times, full fret leveling/crowning, and one time just one fret crowning. I liked the results. I'd say that a steel crowning file pays off in the long run. All in all i paid 30 EUROs and did 2 full jobs and 1 crowned fret. Cost justified IMHO.
this might be splitting hairs, but wouldn't you need a notched straight edge so that you're reading the fretboard, and not the tops of the supposedly un-even frets that you're leveling and crowning?
Re: How to properly level and crown frets for the DIY'er
This is an old thread but still 100% relevant, and also so I can refer to it later. I do all of my own setups and the carpenters square is something I hadn't thought of.