I have been using titebond 3 wood glue for my latest project. $5(us)/16 oz. It goes a long way, is waterproof after it dries, and best of all, if you get any bare spots, you can touch them up. Remember, silicone will adhere to almost anything, except cured silicone
So if you are using silicone, i recommend using the brown colored version for a couple reasons. One being you can see what you covered, the second being that if you miss any spots, at least it's brown and not clear, allowing the foam to show through.