I get where you are coming from and while I applaud your desire to fine tune your system to its absolute best. This is practical advice and I am sure there are those here that will disagree, the bottom line is for any speaker system you want to drive at high levels and high quality, choose the largest conductor that will work with the speaker binding posts and the ones on the the amplifier driving those speakers and make sure the conductors are 100% copper, or if silver is affordable, go there, but there is little reason to attempt anything beyond that as the influence of those wires on system performance is inaudible. The way the recording is mixed has way more influence over the final sound than any of your interconnects. Believe in the notion of suspending your connection to the room and location, transport yourself as you listen to the space where it was recorded...and believe you are there. Immerse yourself in the music and stop worrying about whether your 12 gauge speaker wires are enough...the answer is nearly always, yes, its enough. Now screw the equipment and savor the music.
Sound file to aide in speaker wire comparison
Wondering if anyone knows of a sound file that would play the same output on each channel in alternating fashion. If trying to compare speaker wires one could configure your system using one set of wires to one speaker and another to the other. Then the sound file would play the same frequencies to each speaker but not simultaneously. Yes you could do this with a mono sound file and flip the balance back and forth, but my preamp does not have balance controls.