And to back up our learned colleague, I once watched the Dan Erlewine DVD where he covered fret levelling and wasn't on the hard stewmac sell. He used a builders level with double sided tape and standard sandpaper trimmed to rough width with a scalpel or stanley knife after sticking. The one sheet length wasn't long enough to cover the surface of the level so he just butted the trimmed off piece right up to the first bit, stuck it on and trimmed to the same width. Worked a treat.