If you have a true 100% Mag setup with no external coil, whatever electrical system installed on the tractor has no bearing on the ignition system.
Edit: the only wire you need be concerned with is the kill wire for the Mag to shut the tractor off. Other wise it doesn't matter if it's 6v, 12v, Cutout, Regulator, Alternator or Generator or any combination in between when using a Mag.
