I've had past setups as low as ~ 7.1 Hz calculated resonance; with that cart (Ortofon MC Windfeld) I had phenomenal bass quality/impact, amazing detail retrieval, and razor-sharp imaging, but the top end was too hot for my tastes -- possibly a result of the cartridge's character combined with my speakers (seems unlikely to have been caused by a 7Hz resonance). I do prefer Koetsus, after all. I suppose it depends on your turntable and any warp controls (ring clamp, vacuum hold down) you may have implemented. I had neither.
You could use a lighter headshell to move resonance up into safe range. Ortofon sells an oak & Urushi lacquer headshell @ 9.5 grams that would get you above 7.5Hz. I've used that shell on my high-mass Fidelity Research arm.
You can also get headshells with adjustable azimuth, but that feature usually brings along higher mass. I'd go for a lighter non-azimuth shell; the 2M Black may sound excellent with azimuth fine-tuning, but it also sounds very good on non-adjustable arms.
That Ortofon arm looks like another Jelco-built unit with Ortofon mods; it should be nice. However, by the numbers it's going to be a more natural match with MC carts like the Cadenza series (the Cadenza Red being a very worthy upgrade over a 2M black). I can confirm that the Cadenza/Kontrapunkt series worked beautifully on my own high mass (20g) S-shape FR64fx tonarm. That line has a nice low-ish compliance of 12, great for an 18-20g arm.
You could use a lighter headshell to move resonance up into safe range. Ortofon sells an oak & Urushi lacquer headshell @ 9.5 grams that would get you above 7.5Hz. I've used that shell on my high-mass Fidelity Research arm.
You can also get headshells with adjustable azimuth, but that feature usually brings along higher mass. I'd go for a lighter non-azimuth shell; the 2M Black may sound excellent with azimuth fine-tuning, but it also sounds very good on non-adjustable arms.
That Ortofon arm looks like another Jelco-built unit with Ortofon mods; it should be nice. However, by the numbers it's going to be a more natural match with MC carts like the Cadenza series (the Cadenza Red being a very worthy upgrade over a 2M black). I can confirm that the Cadenza/Kontrapunkt series worked beautifully on my own high mass (20g) S-shape FR64fx tonarm. That line has a nice low-ish compliance of 12, great for an 18-20g arm.