I can say what NOT to use, silicone! It does not adhere well to smooth surfaces, loosens over time-allowing water to leak past the loosened seal, and if it begins to loosen you can pull the entire run off at once. When it is removed it leaves a residue that requires a special cleaner to remove or nothing else will stick to those surfaces.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"