I guess sooner or later it will have to be redone but for now this will do.

I picked up the panel fasteners at Advance Auto, and the glue I had but is great stuff I got at Hobby Lobby.
The glue is well known in the audio world for its good use for speaker surround adhesive. It dries clear and does not expand or contract when curing. Good stuff.

I used the retainers shown on the bottom and displayed in before and after I cut them.
The retainers at the top are from an assortment package.

I had some grey paint used for painting flexible plastic that was a nice convenience.

I used the knife to cut a small X on my marks and applied the glue (sparingly) to the gills.