Awesome job of reinforcement it sounds like! ..too bad I couldn't help ya smell the fumes ...lol ...you didn't miss a thing with your wiring eitherWhen I mounted mine I cut some aircraft structural foam to fit under the plastic box. I put 2 layers of fiberglass on the foam and then epoxy bonded it to the steel floor. I made sure that my battery also rested on the tubular structure in front of the opening to the rear. I epoxy bonded some aluminum flat to the bottom of the plastic box and ran my tie down bolts through the aluminum.
I used a battery separator that favored the stock battery for charging and wired it so that I could use both batteries together if necessary. Also works to start the unit if the main battery is down.
Added a fuse block and ground and wired my winch and all accessories to the second battery.
So far works good.