I used Fusion on all the plastic parts of my trailer about 5 or 6 years ago because of yellowing and those parts still look like new (window frames on both doors, stove hood vent cover, door holders, grab bar anchors etc.).
About three years ago, I used it on the covers for the air conditioner, and the refrigerator vent on the roof. Both of those items were starting to become brittle. They now look like new again and have lasted another 3 years and going strong.
I think that Fusion paint will probably be perfect for what you want it to do.
Barney