Are you sure that the 12 gram mass of the Technics arm is without the headshell?
Here is another calculator!
http://www.mh-audio.nl/Calculators/RF.html
And another!
https://www.vinylengine.com/cartridge_resonance_evaluator.php
Here is another calculator!
http://www.mh-audio.nl/Calculators/RF.html
And another!
https://www.vinylengine.com/cartridge_resonance_evaluator.php