RE: Lets try a splitter board/mold
Next,
#1 We want to seal that little tiny gap between the splitter edge and in this case the wing edge. Make sure your part is clean and well waxed with a good mold release wax at this point.
#2 I used some tub and tile caulk to seal the edge, put a bead down only about 4 or 5 inches at a time.
#3 use your finger to spread.
#4 gently wipe with a damp paper towel to leave only the gap filled. Only do 4 or 5 inch long sections at a time.