I've taken it apart a dozen times and reassembled it with the same results. I've hunted for sprue bumps I may have missed cutting flush on the diffusers and using tweezers to tuck the LED wires into places that would not affect them, and the results are the same. The gap is worse on the Port side than on the Starboard, and forcing the hull down and holding it into position in which I would cement the hull top to the bottom, makes the warping curvature worse from the bow to amidships.
I've put the model aside for now due frustration and I may revisit it in a few weeks or more. I'm toying with scrapping the LED system it came with and just putting in my own LEDs as I continue to suspect some of my problem is the length of extra wiring that has to be wrapped around and cinched into various areas on the diffusers before the bulb is inserted in the grips. To eliminate bad light leaks in the superstructure means I will have to glue down the superstructure to the hull - or come up with some kind of light blocking and that would likely kill being able to turn it on and off with the LED system the model came with. So, if I order my own, I can get a remote and only have to worry about lifting off the top when changing batteries.
But for now, I have set it aside.