Gorilla Tape has worked well for me. I used it for my elevator gap seals more than 3 years ago and I just recently replaced part of it mainly because it had yellowed. It's super strong, sticks good and the price is right. The roll I have would probably do 20 airplanes. Years ago a friend came up with the idea of using book binder tape.. It's clear and strong and will last a couple of years. My buddy's Carbon Cub uses a rubber strip that presses into the gap. That would be the ideal solution if something like that was available for the Kitfox. I've seen them available through some of the aviation parts suppliers and of course the prices are outrageous.