How thick is the roof on Lance 815? Blueprint + wiring diag?

Btw, I dug around the converter box, its manual, and am now reviewing the Lance owners manual as well. I won't be changing it out, but my solar and battery bank system with inverter that I'm building will be entirely independent from this factory system. Redundancy, safer, easier, reliable... I put a good new battery back in the normal compartment (tested it, then left it disconnected again as the rig sits most of the time).