I was thinking "the added lip" would be more about light bleed through the gap the two parts create,It's the warping that's the problem because the model is a large, open, relatively thin part which isn't suited to a resin 3D print. Even if there was a lip, if the part is warped it won't keep the parts together with only 4 corner screws.
I'm going the PETG or Nylon route given its structural benefits and rigidity which is better suited to thinner parts.
not fixing the warp that shouldn't be there.
Of course, they would have to be printed without the warp in the first place.....
Anyway, good luck.