I’m surprised the "highish" compliance 2M Black is working so well in your "heavyish" tonearm. If my math is correct the RF is in the danger zone at 7Hz.
I’m also surprised at all the recs here touting high compliant carts that are much better suited to lighter arms than your SME.
If I were to disregard compliance matching and make such a rec, I’d say consider the Cartridge Man Music Maker. Best high output cartridge I’ve ever heard. Haven’t dabbled in the vintage cart world, but I have owned and heard many of the recs made here. The CMMM slays all of them in terms of saturated tonal colors, image density and plain ol’ musicality and "you are there" involvement.
Although a bit on the springy side, it is fantastic on my medium mass OL Encounter Mk3c and Rega RB300 (BritAudio re-wire) arms.