In the picture below, you can see that the upper trailing edge "seal" is supposed to be a bent piece of 1.5 mm plywood. After struggling with trying to get the plywood to bend around a 3/4 inch radius (I even tried 1 mm plywood), I decided to make it the same way as the lower "seal".
It came out much better than the previous two attempts, and the designer even said he'd update the plans to use this method!
Update: Although I doubled up the plywood on the top piece, the designer indicated that doubling up the plywood on the top piece is not necessary.
Total Time: 16.0 hrs.