Teardrops n Tiny Travel Trailers

First new to the board so be gentle lol. Have a 1995 6x12 Hallmark that I got the bright idea to convert to a RV (someone shoot me) I am a union carpenter with the skills to think way to big so here's my question.

I demo'ed the rear of the trailer and have welded the framework to have an 18 tall by 30 wide cargo door at the bottom and a 37x 57 door on the top. The larger door is for a "pop out to slide a full mattress out to give more interior space.

My question is what piano hinge would you recommend. I would like to use an aluminum gear hinge but am really questioning how it would hold up in a horizontal application.

Total static door/hatch weight should be 250 to 300 lbs (steel welded frame double 3/4 plywood and mattress) am thinking need to put fail weight at 750 to 1000 lbs to account for wife and I sleeping and "not sleeping" on it.

The door will be held in place when open by 1/8 inch flat stock bolted to frame.

Am I over engineering and what piano hinge should I use

Piano hinge will leak, the gear hinge should be fine. I have used them for galley hinges. I would take some weight out of the bump out. Feet don't weigh much. My bump out for my feet is 3/4" Plywood skinned with the same this aluminum my sides are trimmed with.