I need some help. I am wiring up a 5.1 setup in a new home. A friend of mine gave me 300 foot of in-wall 4X16 speaker wire. Each run will be anywhere from 30 foot to 60 foot. Would I be better to get new wire 14 or 12 gauge, use the wire as it is, or use the wire but use 2 of the 4 wires for the positive and 2 of the 4 for the negative?