Here's an article that might help you calculate RF:
https://www.remusic.it/EN/The-Compliance-of-a-Cartridge-and-the-Resonance-Frequency-of-the-TonearmCartridge-Combination-05728c00
https://www.remusic.it/EN/The-Compliance-of-a-Cartridge-and-the-Resonance-Frequency-of-the-TonearmCartridge-Combination-05728c00