I am up against this same thing right now. I just finished caning a practice seat, which I will put on my daughter's double paddle canoe. My biggest concern on the seat back is that most the ones I see, like in your link, are not very tall. Where does your backbone rest on these? It seems like the odds are that your spine will be riding on either the upper or lower crossbar instead of the cane, so the taller the better. That seems like overkill somehow. Another thing that puzzles me is the seat backs I see that are apparently in the rowing position. Can you really row with a seat back behind you? I think most of the historic backed seats were only in the passenger (or sport) position. I guess I have a similar concern on the double paddle canoe. You want quite a low seat back to allow free movement of your back. I can't figure out how cane will work for this application. A kayak typically uses a suspended low backrest, which can adjust itself to your back.
