Zig, Split Charge, Leisure, Understanding it all

Doing this as soon as I get back.

 

The Durite might work backwards and charge the main battery from the ZIG as well as the leisure battery.

 

I need to divert my interior lights (one on the pop top the other above the sink) on to the leisure battery, anyone know where i should pick the feed up from, short of pulling the interior out. I plan to put a new radio in the back so can plan the wiring for that.