If you have one of those hand grinders with no reference point for the grind setting, you can drill a little pit or two in the metal to act as one. (I tried marking it with a file first, but that didn't really work.)
This is a Timemore Chestnut C3 grinder, but I'm sure the same works for a bunch of other grinders.
A great and simple solution! I love the super-short blogs by the way.