Enclosed trailer/semi ramp winch

I bought a 99 International box truck (old moving truck) that will work perfect for hauling my sleeper truck around. I want to build a rear door for it that also doubles as a fold down ramp. Similar to what most of the super stock trucks and tractors use.

I believe I have the design of the door down but cant remember how guys are setting up the winch for raising/lowering it. Do guys run two winches, one for each side, or just one winch on one side, or one in the center that you take off to get the vehicle out?

Just looking for ideas before I start buying things I dont end up using.

Door ideas are also welcome. Latching in particular.

One winch in the center than can take off. I suppose you could get a garage door opener and use the rotary spring cables on it.

Most I have seen mount a smaller winch up high to pull the door up. What kinda door is on the truck now? Seen some leave the doors how they come and buy aluminum ramps that hook on the back that can slide in when truck is loaded

Single winch up top is what I've seen on most. Saw one break most of the way up, not pretty and very bad if someone had been under it.