Gain setting for both pre-amp and Audio Research power amp w/ high output cart

Greetings.

I just put together an all-analog system consisting of a Rega RP40 TT with an Exact 2 cart, a Spectral DCM-10 pre-amp into an Audio Research Model-115MKII power amp. With a cart that is crazy high-output, my gain settings on the Spectral preamp are set to roughly 10 on dials that goes to 100, and an educated guess that the gain dials on the AR power amp are about 30% from zero.  So low gain.

LPs do sound amazing, really. Better than I ever thought possible in my room. There’s still a good amount of groove noise between tracks and in very quiet passages at hi volumes which is expected with that 6.2mv cart.

Question is, is there a relationship between gain on preamp to power amp in this situation that could alleviate some of the noise? Could I possibly go even lower on the preamp or maybe more preamp gain, even less power amp?

I expect simplest solution is to change to a .4mv MC cart but I’m not going to do that just yet. But is that the only solution?  It's hard to play with the preamp gain on the fly to experiment which is why I'm looking for direction.

 Any advice?

 Thanks much!