John, the answer to your question is yes, you can use the right material directly over the existing, and the Eternabond will hold up to the wind. The VERY most important aspect is clean, clean, clean. No off-the-wall solvents promising to be the very best. Your choice of spray cleaners, 409 comes to mind. Dollar store has a 'Purple Power' cheap stuff that people swear by. A small scrub brush, a squirt bottle, rinse twice with clean water, let it sit until it is bone dry and you're ready to go.
Jim and DW 48 years Brenda
2017 38rssa, also a 2015 Salem (for Alaska)
2019 F450, ruby red
Harley Road King & sidecar