Re: gauge of wire for Alternator to battery?
 

#4 or 6 welding cable works very well

Re: gauge of wire for Alternator to battery?
 

Unless I missed it you do not have to run the alternator charge wire to the rear where the battery is....you already have a battery cable large enough to operate the starter in the car so all you need is a cable of enough capacity to go from the alternator to the junction point of this cable (starter solenoid)...that is why you don't need a real large wire from the alternator to this point (short run)......also the charge signal from the alternator can be very a "dirty" signal (not real clean) and this can cause all kinds of RF in the car if not handled well......

D L Rambo.....