Portal folks, We need to seal our Fleetwood's roof-mount tracks, and also the corner roof caps. Like many, I've fallen into the abyss of over-analysis after reading too many posts about caulk. I've come to the conclusion that Sikaflex 221/715, Dicor self-leveling, and 3M4200 are all acceptable choices; and have learned that self-leveling versions should only be used for horizontal, but not vertical surfaces. Sounds good so far, right? Please tell me which of these sealants you would use for the aforementioned job on your own pup, and why. If possible, I'd prefer one that would work for the roof tracks and corner caps, and am leaning toward Sikaflex 221. But then, I read it tends to yellow with UV exposure? Thanks for your opinions!