Onboard Charger

I am toying with the idea of adding an onboard charger. I think this would be straight forward (Probably still is) if not for the Blue Sea Add a Battery system that I have. I am trying to figure out the best way to wire it. I understand that similar questions have been asked but nothing that I searched included the add a battery. Which option would work best. Please keep in mind that the leads coming off the onboard charger will not reach my house batteries. The charger, add a battery, and starting battery are under the passenger storage compartment, while the "house" batteries are in the rear lockers run with 0 gauge wire.

Thanks in advance
Current Setup

Option 1 (I understand the switch will need to be on for it to charge)

Option 2 (Again due to distance of batteries from charger)

Option 3

I am not completely set on this charger, just used it as a reference tool.