We have 18 yr old exterior black shades. These would be of the 80% filter variety not the current 90%.
We also have snaps and twist fasteners mounted on the rig. Sometimes it is a challenge to install the windshield shade in cooler weather because it does not stretch easily any more. But, wind has never removed the shade.
I would probably go with the Earth Magnet exterior solution if replacing the current shade.
I like the magnet idea because one could mount the shade on the inside or outside depending on the circumstance.