Exterior
Cedar is one of the most rot resistant woods, and certainly of the local woods in Northwest. Every kind of installation would require a different approach, In my experience with boat building (the most harsh environment for rot/water damage) sealing the end grain of any board is the most important part - If you don't want ANY weather to show over the years, you would have to use a finish that develops ontop of the wood, not a penetrating finish. Cetol, or tradtional oil based marine varnishes work great but are a lot of work! If your okay with some aging/weather showing go with the pentrating oil finishes. Dalys finishes in Seattle has many options. Good luck!
Love the windows and all natural light/outdoors
Q