We installed this bug screen
a few years ago, with Velcro dots; it was only a quick test fit for a trip, but it worked very well and needs to be made more permanent. The problem is that mosquitos crawl under the tiny gaps in the upper edge (because the under side of the hard top is white and well lit at night, there are hordes). Overall, not many get in and it lets a lot of air into the boat.
Sail Delmarva: Banning Bugs - Slider Screen for a PDQ 32
I'm think a continuous Velcro strip, with ties to hold it up when not in use.