I've got the whole thing down to a piece of card with 7mm spindle hole, and two straight lines. One line to be set exactly between the spindle hole and pivot, extending beyond the spindle hole somewhat. Another line to make the tracking offset angle with the first line, and crossing the first line exactly at the overhang distance beyond the spindle hole. Set the stylus exactly on the intersection, and align cartridge so that the second line exactly passes along the centre of the cartridge/cantilever. With the first line lined up between spindle and pivot.
I think this is so straightforward, cheap, quick, flexible and produces good results. No gauge required !