Hi Bill,
I'm not familiar with the OEM installation of the wood framed windows on your Marine Trader. I can only offer my experience with living with wood framed windows for many years on my Canoe Cove. The Canoe Cove had a fiberglass cabin, cored with a teak veneered marine plywood on the interior. The frames were let into openings in the cabin sides, and screwed through the fiberglass exterior into the plywood core. Teak trim was screwed back through the core from the interior to trap the glass, and complete the install. I'm guessing your Marine Trader is similar.
The Canoe Cove OEM installation of my teak window frames used Sikaflex 291 as a bedding compound. I continued to use it for many years when performing the difficult and tedious task of maintaining and repairing the windows on my boat. And you WILL have to re-bed and re-caulk at least some of your frames and glass with regularity to maintain a water tight seal. And I further suggest you plan for replacement of window glass, should something untoward occur.
291 is sufficiently viscous to allow the screws to bed the frames properly into the salon window cutouts, is very easy to tool into fillets around the frames and window glass, and is removable in the future without damage. It forms a tenacious bond with window glass, assuming the installation instructions from Sikaflex are rigorously followed. It is also available in other colors (mahogany, for instance) should matching natural or bright-finished teak window frames be of interest.
In my opinion, use of butyl tape for this purpose, in combination with screwed-in-place wood frames, is absolutely not appropriate. The tape is too stiff to allow the screws to bed the frames properly, without either deforming the frames, and/or stripping the screws. Use of household products in the marine environment for window frame bedding and sealing is equally problematic, as the household environment, even immediately on the foreshore, is NOT equivalent to a marine environment. Dunno about your house, but mine doesn't vibrate and flex while underway in a seaway, as does my boat. While 291 is spendy, you gets what you pays for.
3M4200 is also a fine product for this application, both for bedding the frames, and forming filets around the glass. Same viscous nature, same UV resistance, same cost (more or less) than Sikaflex 291. Different installation procedures though-make sure and check with both Sikaflex and 3M should you chose to use their products.
Again in my opinion, NO NO NO silicon-based products. Never on my boat, anyway. Ditto for 3M5200. Great adhesive, lousy caulk.
Regards,
Pete