I tested the thickness the seal was required to be in various positions and found a large variation, that is why I used a foam seal, as it conformed better. The coupe seal should be higher at the top Center opposition or a well is formed for water to sit. Dirt would also sit there, get damp and start rust. Some rope seals stick to the paint too well and it might be impossible to remove the wing again.others used a silicone seal and again it would be impossible to remove the wing later for whatever reason, maybe a poor seal and another leak.