12 AWG Mains Power Cable From Wall To Power Conditioner Sufficient?

Yes.  That's probably thicker than what's in your wall, which is most likely 14 gauge, unless you have a 20 amp circuit. You can't make the 14 gauge in your wall suddenly perform better with thicker gauge wires.

If you want to overkill a little, sure go ahead and get 10 gauge, but I'd be careful overspending.

Agree with "yes"

Thanks for the responses. Appreciated.

Im over killin with some furutech 3ts762.This will be diy project fwiw.

Digsmithd, I was initially looking at the Furutech 3ts762 but was told that it’s a stiff cable with average sonic performance. The TCS31 was recommended instead as the 2nd best cable just below the DPS4.1. TCS31 combined with FI-50 NCF(R) is a killer classic combination based on few reviews.