In 1980 I did a survey of around 60 cartridges, and the mean distance from cartridge mounting to stylus was 9mm. Some 95% were between 6.5mm and 11.5mm, i.e. within +/- 2.5mm, with a few outliers.
While the data is well out of date, there are many cartridges from the seventies and eighties, or their later derivatives, still used, still in production, or available second hand.
So for budding tonearm designers, have the adjustment at your base, or the slots in your headshell, long enough to at least accommodate that variation, if not more.
