Super belated thanks for all the help guys. I'll have a crack at Inkscape to see if I find it any more intuitive, but have been finding Illustrator ok so far (if very confusing).

I do have one question for anyone who uses Illustrator (here's looking at you Sonic). how in god's name do you set scales for things? Like the width of the nut, or the length of the neck? I've done some googling but am drawing a blank (possibly using wrong terminology?)