Hi,
Just installed mine so thought I'd toss this out FWIW.
I take the enclosure off every year and give them a good cleaning and then treat the plastic glass before rolling up and placing in storage.
I have tried a number of things. I like the Meguiar's plastic cleaner and polish. A two step application that takes some elbow grease.
I like the way Plexus finishes them, so I clean in the fall and finish them in the spring.
This year I tried the cleaner and polish from 210. Ok I guess, but I like the Plexus better as the polish and didn't think the 210 cleaner did much.
Be careful of bleach on the white enclosure (if you have white). Spot clean only. The thread material doesn't hold up so well.
Re-installing. I find it best to start from the front and then the sides followed by the 3 in the aft. I put the 2 corner pieces in last due to the issue at the aft we already discussed.
Up here in the NE, a lot of people just leave them on the boat and shrink wrap over the boat. No problem with this except difficult to clean if you are using a liquid. Ok if you are using an aerosol spray though.
Good luck.