I want to use cherry for the gunwhales on my next s&g canoe but I can't get it any longer than 10 ft. I plan to make them 3/4 by 1 inch. The scarf joints on the 1/4 in. ply are 2 inches long. Does this mean the joints for 1 inch should be 16 inches long? This doesn't sound right to me. Is there a formula? Thanks for any replies.