Whew! Post is a little run on...
Try the Red into the PL. It’s not going to hurt anythingng.
I use the same model with a .4mv into a tube integrated
On paper, a little low, suggesting I may be loosing out on full potential dynamics. In my setup and my ears, no need to bump volume. I hear nuances of familiar cuts. Maybe the cart/PL specs isn’t exact, who knows/cares-whatever.
Linestage typically add 10+ dB gain, so you’re at 70dbs or so. I don't know what/if the Marantz adds?
Are you aware there is a FREE Upscale mod for the PL?
I haven’t bothered with it. Inquire and they’ll give details.