It seems to me, and I could be all wet (pun), that this galley leak problem may be fixed with a water diverting mechanism. They make a rain gutter material for RV's that is fairly small.... If I were you, I would visit an RV supply store and look at some of it. Maybe the RV place could also recommend a temporary glue to use so you could try it. You might be able to attach it on the roof, just above the hinge, but far enough away so the hatch doesn't rub on it when you put it up.
If nothing else, you could temporarily attach an uncut piece with rubber cement and try flooding the top of your tear with water from a hose to see if it helps. Just let the excess gutter stuff hang down on the sides for this test. (Rubber Cement peels off most surfaces; but, try it on both the tear and the gutter stuff in inconspicuous places to be certain it will work okay and not harm anything.) If it doesn't work, peel off the RC and take the unblemished, uncut gutter product back and get a refund.
If it works, you wouldn't need a lot; and, if it sits too high and looks offensive to you, you might be able to trim it down some....don't know....It's just an idea

...Might be worth a try.....