64 Valiant charging and lighting/gauge issues

Thank for the help so far!

I changed out the voltage regulator and hooked up my subwoofer amp. Now the amp gauge isn’t moving at all. I drove it around and ended up with a low battery. Got it back home and started looking at it. I tried disconnecting the sub amp...no change. I put the old regulator back in...no change. I’m thinking the sub amp killed the alternator by pulling too many amps.

So with all of that...I want to have the alternator bumped up to 80-100amps. I understand that’s a bit much for the stock wiring. I know I need to run some heavier gauge wiring to compensate for the increase in amps. My question is what wires? I feel I should bypass the factory amp gauge at this point, right?