Maril: Some thoughts to consider on your narrower set of questions. If you have one line feeding multiple receptacles or receptacles plus a distribution box, you have the advantage, I think, of eliminating the different grounding potential among separate dedicated lines. I think this is the "British" style, if I can label it as such. Downside would seem to be that you are limited to what- a 20 amp line shared by multiple devices? (Leaving isolation of the digital to one side as you suggested).
You may remember, I also have the ML2 and you are right that they don’t draw a huge amount of power, but I know Vlad always harps about not using conditioning to bottleneck the current to his amps. I don’t know if a shared line (even of all analog) would be limiting.
I also have the Duos (though if I recall, you have newish ones). I wound up installing 4 dedicated lines in my room. The downside to how it was done was that all the lines were bundled together when the conduit was brought up from the basement, so when the air compressor motor for my tonearm kicks on, it affects the other lines. (This came up in another thread- I think Jea had pointed it out). So there are some best practices, not only to gauge, per CLeeds, but other aspects of how the cabling is done, from panel to room.
I’m not sure you can have a local distribution box in the room that is hardwired under applicable code, but Jea, or someone else here with real electrical knowledge and skills can address that better than me.
It’s great fun to plan a new room- i’ve been doing it mentally for several years, waiting to relocate. I guess the biggest limitation is that this stuff is "in wall" and once done, it’s a mess to re-do or add on to. Dunno if that helps....
