Well, not in my attempts. Have you just used a crowning file? You'd normally run a flat-bottomed fret levelling file all along the top of the frets first, having first marked the top of each fret with something like a Sharpie pen, filing until all the Sharpie marks have gone from the top of the frets. Then you use the fret crowning file, then run through the polishing grit sandpapers/micromeshes.
I try and count the number of strokes with the crowning file and do the same number on each fret. The same with the sandpapers. It's not perfect but it does keep the frets pretty much the same height.