This solution is close but not quite complete. I've studied this a fair bit and the side rails of the cobra trailer, at least mine is not quite as stout as one would think. You can actually flex it with just your hand. Its only 1/16th inch material and unclear how well mounted to the lid. I am concerned about buckling the side rails for trailers with large displacement issues once you start cranking on the jack. If it buckles, you're screwed.. Interestingly the trailer top struts are not mounted to the side rails. They actually mount to a cross member that is glassed to the lid. I think something like this cross member should be added to the location of this jacking mechanism to help distribute the load to more than just the rail. This will also be synergistic in taking vertical loads associated with the jack for those that have an angle to deal with (rail w.r.t to the hinge plate of about 5 degrees) instead of torsionally loading the side rail.