That leading edge tape isn't very transparent.
I would find some gaffer's tape in a color to match the car. Lay down a protective layer of gaffer's tape around the perimeter of the opening, then cut a piece of thin acrylic sheet to fit the opening. Tape that in place on top of the first layer of tape.
If you take the time to cut the tape nicely, I think it would look OK. I doubt if you would want to screw into your bumper
like I did on my Vibe.