I'll double check my wire size at lunch. Its a super flexible XSpower cable, about twice as flexible as welding cable, so a smaller size can handle a wee bit more amps.
I'll find a picture of my setup for ya. And the two smaller wires are for the alternator.. You run from the dash back to the switch, then from the switch to the alternator. I actually run two pairs of the speaker wire. This way you can have constant power for your stereo and other things if you need.