I dislike trying to rember numbers and doing quick math in my head. So I slap a thin band of tape over the distance scales on my camera and write a flash/aperture scale for whatever GN I happen to be using over it. Just calculate the f-stop of each for each mark on the lens and write that f-stop over it. Its a lot easier to focus, glance at the barrel and read f/8 off it then trying to remember which stop to use at each distance, or doing a quick calculation in the head.