John, there certainly should not be any audible differences between 12ga and 14ga wire. Unless you are running in excess of 100 watts for hours at a time, I wouldn't give the matter any more thought. At "normal" listening levels you just aren't going to get anywhere near the maximum current or voltage rating of the wire. (Diving in the foxhole now to avoid all of the fire from fans of high $$$ cables).
I think having all of your speaker outputs set to 0 just sounds odd to me. It would seem that unless you have a perfect room, at least 1 of them would calibrate a little off of 0. Did you run the calibration built into your receiver or did you use the SPL / Avia method?
Waiting for Fed Ex now!
