Well for one, your ground wire just needs to ground to your body, doesn't need to go to the battery. And your power wire basicly denotes the size of your ground wire. What i typicly use in all the setups i use is a 4 gauge wire. It usually is enuff, although a 760w pioneer MIGHT... imfasus in MIGHT need a 2 gauge, never dealt with them so i can't give you an exact number. If it were me, id use a 4 gauge power wire/ground wire. Its kinda hard to tell until you hook it up, but you might also need a capaciter. Easiest way to tell is to run the system at full blast at night and see if your headlights dim, if they dim a teeny bit, don't worry about it, but if it is noticable *like mine, people thought i was a cop or something and moved out of my way
* then you will need to invest in a cap.
I myself run an MTX 350w amp with 2 mtx 12"s a pioneer 100w amp that powers my 6x9"s and *ghettoly* rigged to my front speakers. Also in the loop is a 1 farad capaciter and a crossover *that isn't hooked up right now due to it wanting to act funny, pretty sure a bad connection inside on of the level adjusters *potentiometer for you technicle people**
Final Thought: Use 4 gauge, should be enuff, ground to the body, might want to look into upgrading your chassis ground from the battery itself to the body also, Kinda pointless having a 4 gauge ground wire to the body, but only a 10 gauge ground wire from the body to the battery. And maybe a Cap