Several years ago I had the windshields re-set on our 96 Southwind. The shop removed both windshields, cleaned the gaskets and reinstalled the glass. They said the factory did not use enough sealant.
I've had no leaks or problems since they were re-set.
I would not use silicone. If it doesn't stop the leak, nothing else will stick to it properly, including more silicone.
You may want to consider taking it to a glass shop and having it repaired properly.
If not, I would use Dicor, for vertical surfaces, not the self leveling caulk.