@devinplombier , I just wanted to clarify that what the author was suggesting was beyond cutting out holes for duplexes and fishing romex down through them. I have no intention of "stepping down" 6 or 8 awg to 10.
As it is, every dedicated circuit (six so far) I have installed I did with 12-2. Unfortunately, I didn’t have the internet when I dived into the first project, and during subsequent expeditions I guess I wasn’t convinced that 12-2 wouldn't/couldn’t carry the current satisfactorily and I kind of got the impression from electricians I talked to (not on the internet) that 10 gauge is difficult to work with. I am still not convinced that gear plugged into 10 gauge will sound better, but maybe I am just in denial, and I may go back up in the attic and swap out three of the runs I did with 12 and use 10. Just in case.
For the time being, I guess my first goal is to get my new 2m power cords plugged straight into the wall with nothing in between, and that is relatively simple and wouldn’t even require a trip back up to the attic. Unless I wanted to space those three runs out some more where they go down the wall, and I guess I probably would.
I appreciate the respiratory advice related to working in the attic. I’ve gone from full blown respirators to dust masks to this last expedition--nothing. You probably understand what it’s like to work up there, crouched/kneeling/whatever on a plank that is sitting on a couple of ceiling joists or rafters or whatever one may call them, and all the other discomforts of working in an unfinished attic . . . the older I get the harder it gets and the easier and quicker I start cramping up when contorting my body to work in the places I need to work up there.