comparison of different dedicated AC line types?

if you won't find anyone done the exact comparison, you can do that on your own hiring electrician and requesting him to provide a couple of different dedicated lines that you're gong to be experimenting with. make sure that he doesn't take you as a nut case tho.

Thanks for your responses. I am capable of running the wiring myself as I was a mechanical contractor.
Thanks to Lak as you have done what I was interested in. I think I will run two different ones to see if I notice any difference in my setup, then go from there.

I would run 10GA to an amplifier.

It's an AC line. Nothing special is required. 12 GA should be fine unless you have very large amps. An AC power line is a noise source, so it is silly to shield it.
The whole point of an audio equipment power supply is to stabilize and clean the power to the electronics. If you have adequate current carrying capability, you are fine.

Speaking from experience with a friend who went through numerous steps upgrading his dedicated AC line, solid core is better than stranded. Improvement achieved going to !0ga replacing 12ga, and additional improvement going to 10ga Cryo'd Romex from VH Audio (no affiliation) replacing the standard 10ga Romex. Also, better to have at least 2 lines, one for analog, and one for digital. He was not using a very high power amp, but a high quality 60 watt pure class A.