Hi James, you can reduce the width of the tape side-to-side too and that will reduce its resistance somewhat. I would probably do what you are suggesting; remove a little material from the hatch lip. I would use a router plane or a regular electric router. I might add reinforcement to the underside of the lip too.

Another option is to experiment with other gasket material. I have some thin minicell and thin neoprene that would probably work. Check your local kayak or dive shop.

Good luck to you,
Chip