...well I just got out of the hospital...
Just kidding. The installation went fine. Mounted the box to the floor of the boat next to the engine. Got a 1-2-BOTH-OFF switch, hooked the batteries up to it, and hooked the bilge pump up to both batteries. It's been a few weeks and the boat's all hunky-dory
If anyone wants to do the same to their boat, just shoot me a PM.