Hey there good luck with the build!
I’m kind of in the same situation I have a GMC Savana that has the full down bed in the back. Now my bed has an electrical motor that drops and lowers which is super Austin Powers shagadelic honestly call Mom but the motor’s require extra support beams underneath
A motor that sometimes gets disconnected
And the folding apparatus has steel or some type of uncomfortable metal beans around the edges and parts of the interior of said panel
I left my installation on because I got my van in the winter and I didn’t want to reinvent the wheel when any kind of warmth right now would be viable
I am about to take that bed out finally it just hurts too much to sleep on now after 6 months of daily use all of the springs and bars poke out.
I would love to see what you come up with oh, that is just my experience with my van. I really do want to keep the walls with the carpet on the floor has got to go LOL good luck and happy travels