There is also my favourite way for "rounded" tailsurfaces Don. Build the ribs and spars as a conventional wing. Then "tack" 1/16" balsa sheet between ribs where the edges are curved. The 1/16" sheet follows the edge curves of the tailsurfaces. Once done I then soak 1/16" x the thickness of the tail, strips of balsa and glue 3 laminates to the ribs and 1/16"sheet using thick cyano(one laminate at a time). The CA dries very fast as the wood is wet so you only hold in place for a few seconds as you work your way round the outline. Once dry..the 1/16" sheet is cut out so only the spars ribs and edges are left...sand to shape. Very strong as the cyano hardens the edge laminate. Thats how I did the curvy profile of the Jenny and Batboat. Proctor use cane/bamboo for the edges but I didnt have access to any ..and even if I did ..would probably do it the way I did..