Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I plan on using Dolphinite to seal only the screw holes. Companionway trim is not a structural joint so an adhesive is not necessary in my opinion. I plan on removing my trim in the winter to spruce it up.
You might want an adhesive on the hand rails to help them stay stuck to the deck for safety purposes.
I like polysulfide caulk, such as Boat Life, for most things I want to be able to remove in the future. It's much easier to peel off later than that gunk Catalina uses. (Polyurethane caulks are much more adhesive, and can damage the teak later.) I sealed the exterior companionway trim pretty thoroughly to prevent water from getting in behind it. Same for the handrails--don't tighten them down fully until after the caulk has cured--then crank them down a little for a nice gasket effect.
I'm a polysufide guy too. I usually do the perimeter and around holes in an application like this, polysulfide or silicone is a pain to remove from teak, especially silicone, for you next bedding. Silicone would probably be OK if you applied it to the fiberglass and let it skin before you set the teak. Plumber's putty gets brittle, so I wouldn't use it on a boat
Just did this a couple months ago, and I used silicone. I think if you finish the back sides of the teak, getting the silicone off the next time shouldn't be bad. Time will tell...
You should definitely seal not just the screw holes, but put a bead or two along the entire lenght of the pieces. This is your seal to keep wind-blown rainwater out of the cabin. Especially important on the sliding hatch cover trim.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.