The rubberized magnet material is a good idea too. I agree that its not very strong. The stuff on the insides of refrigerator door gaskets could work as it is all about the surface area that makes contact.
I have some speaker magnets but one might have to glue them on the top side of the material.

I cannot guess at how much wind actually blows across the cowling versus the amount that goes in. I know it tugs at the Press an Seal film and moisture from the dew loosens them up. I run that stuff under the wipers and down under the hood lip and onto the firewall gasket.

I hope my scroll idea works longer than the film.

The part about the screen edges might have a tendency to ravel at the squares if the wind can whip at it. I'll just have make something and adjust like you are doing.

It is a lot like making soup, you throw stuff together, let it simmer and stir when needed.

Phil