Yeah, Stewmac has a calculator on their site. So you just punch in the number of frets and scale length and it gives you the distance from the nut for each one to 3 decimal places of a mm. Conveniently, Illustrator works to 3 decimal places as well. So I just use the rectangle tool, make them all 60mm wide and then one box of each height. Centre and top align and bingo. I haven't done a G one yet, but I have fender to 24 frets if you want the file? Even just to have a look at how I've put it together? If you PM me your email I'll send it thru.