You can also use this handy-dandy online calculator: http://www.fretfind.ekips.org/2d/nonparallel.php
Just stick in your two scale lengths, string width at the nut (not the nut width), string width at the bridge, fretboard overhang, "0.33258" for the perpendicular fret distance (for the 7th fret), # of frets and # of strings. Leave the rest of the fields as the default, and it'll spit out a spreadsheet of distances and angles. In that spreadsheet there'll be an "angle" column and a "mid to nut" column which can be used to measure the distance from the nut at the centerline and the angle of that particular fret (assuming you have a digital protractor). Mark it, slot it, fret it and you're done. Easy breezy.