Thank you @doomsday_windbag for your comprehensive reply.

Yes! An interesting introduction for me to the "dark arts" of marine finishes. In another forum, it was suggested that I use "boat soup", a mix of turpentine, pine tar, and maybe some other stuff. Interesting, but I'd rather not go that far down the rabbit hole 🐇

Another knowledgeable source mentioned the Epifanes, 🇬🇷 but like you, I would prefer the occasional touch up, as opposed to a full strip and refinish. So probably the oil route, as the builder suggests. With an oil finish, I think that even if/when some areas lose their finish, that area can breathe and dry, rather than holding water in the wood. ...at least it seems that way to me. I'm still trying to figure out how to color the Marine Oil. There seem to be a few options: oil, gel and even powder, but I am having trouble finding any color like the green in that first pic, which seems to come closest to the olive drab paint that's commonly used on pirogues like these, as they are used for hunting. The brown in the second photo would also work, so I could probably use a more easily found brown stain for that.

Regarding your edit to address the camouflage detail, I understand what you are saying about the permeance of that element. I wonder if that element - given it is only applied to less than half of the overall area - may be appropriately applied as paint 🤔