The hinging ramp is designed with a spring loaded latch handle which allows quick unlatching and latching of the ramp. There is quite a bit more work building this than the fixed ramp, but it does have the advantage of being longer overall and self adjusts to uneven ground.
If you are going to fit removable sides to the trailer (using the accessory pockets), the rear ramp dimensions can be adjusted to the corresponding height of the sides. The ramp latch itself is not strong enough to support a load within the trailer, so tying the ramp to the sides to give the ramp additional strength with anti-luce latches or similar is recommended.
When fabricating the ramp latch hinge tube slot, accuracy is critical to ensure problem free latching.
Prior to welding up the latch handle/pin, position the ramp latch hinge tube and clamp onto the ramp frame (put a 1mm shim between the tube and frame). Double check that the handle and pin work correctly and smoothly and that there is adequate clearance to prevent jamming of the pin during normal use.