The PowerMax 75 amper has power factor correction, so you can run it with the same generator watts as you would need for a 60 amper (more or less--haven't done the exact math on that for this post)
Use the fattest wire you can for the connection to the battery bank even though they will be closer together with the batteries moved to the back.
You can also have an inverter in the mix. You can have the inverter`s fat wires to the battery bank and then run the PowerMax`s wires to the inverter terminals as a sort of buss point, so they share the inverter`s fat wires. Your solar controller to battery wires can also go to the inverter terminals as the same buss points. Fusing the pos side wires is by wire size for each branch on the buss point
If you have a Trimetric shunt in the mix on the neg side then that shunt becomes the buss for the neg side wires from everything.
