Thanks for the advice:

I'm going to keep it all 4 gauge.
80A at the battery.
Power and Ground will run to 1F capacitor.
From here, each line (+-) will either run to a StreetWires Combo distribution (CBR44A)block, or to a couple of T connectors with 40A in-line fuses.
Then run to the amps.

I've added an Exide sealed battery (ORB78DT-84), and looking for some 1/0 gauge wire to do the big 3.