The best stuff to use on the seals at about every six months is a Dielectric Silicone Grease. It comes in a tube and a little goes a long way. Just rub it on a clean seal with a cotton cloth.
Well the dealer found out that BOTH rear window seals are leaking and bad. I told them that much. So they are going to replace them next week when they get the parts in. So I guess it's towels on the back seat until then.