There's one problem with this calculation. It doesn't seem to be very well supported by both measurements and listening experience. Have a look at our armtube experiment's summary of findings
. The widest, in tens of grams, variation in armtube weight results in single Hz difference in main LF resonance.
Sonically, there are numerous examples of relatively "stiff" low compliance moving coil cartridges performing wonderfully in very light arms. And, while a lot fewer people do this, high and medium compliance MM cartridges (except Grado) work very well when mounted on heavy tonearms. I vividly remember a Shure V15-IV, beautifully singing its little heart out on a monster Gray 208s tonearm. Gray's effective mass isn't published, but is clearly above 50 grams.
I am not the only one to think that there's something wrong with this formula. Origin Live, who obviously know a whole lot about tonearms, tell their customers to simply ignore the calculations