ok, I'm reading page after page about the cladding.... It's raw plastic made into whatever shape needed from the factory. Bottom line is that it has no UV protection to it. It will fade, then we can treat it... but by no means, put anything that creates a hard shell. It won't stick and will peel/flake off. Remember, the cladding has a slight texture to it so that's yet another deterrent for adhesion.
There are a number of steps that can be taken to prep the stuff for painting or maybe like what some have done (rhinolining) but it does involve numerous steps with numerous products.
So, whichever product is easy to apply after your 2-3 washing, that's what I would recommend...