My son has my teardrop right now so I can’t verify, but what I would try is another layer of the 3/4″ wide foam gasket that you applied to the underside of the galley hatch. Any local hardware store stocks a variety of different widths and thicknesses of Frost King gasket material. I would start with a package the same width as supplied by CLC (3/4″?) but 3/16 or 5/16 instead of 7/16 thickness. I would start at the area you think is leaking and apply a layer of the gasket a couple feet either side of the suspected leak location. The frost king material is very compressible so I doubt that the additional thickness in one area would negatively impact the areas that don’t have a double layer.