Schodack, I would use 6 gauge wire for that. You have options as far as wiring them up. Instead of using the fuses and shut off, you could use the Blue Seas breakers that combine switching. That’s just one other idea. May be worth calling Rich at Hydrilla Gear to help you out, as he would also have everything that you would need and would offer some good suggestions. The only option that I am not fond of that some do is wiring both poles through one 80 amp breaker.