@volumizer, so if using 12/3 instead of 12/2, you would have an extra conductor. This would need to be tied off so it is not connected, correct?
I understand the benefit of twisted cables, although I have never heard of anybody doing this.
Yes, you have an extra conductor, and it it not connected on either end. I'm not sure, but I think it acts like shielding with the twisted Romex.