This is how I approached the same problem I drilled a hole down through the endpour and epoxied in a bushing made from 1/4"ID copper tube and using Nick's plans from his book ( loaded with good stuff if you don't already have it you should get it ) as a starting point for pivot and steering line attaching points and made cardboard cutouts and hot glued them together to make a working prototype before transfering the pattern to a piece of 1/4" black ash, cut it out and epoxied it together and reinforced it with 6 oz fibreglass , with brass bushings in the upper and lower pivot point it all seems very solid. The blade is 1/4" black ash and is a little too wide but nothing that a few minutes with plane wouldn't fix I cut a groove in the top rounded edge of the blade with a round file for the lift line to follow, there is a second line attached opposite the lift line attaching point for downward pressure and tensioned with a 5/16" bungee there is a 1/8" bungee attached at a point part way up the lift line to keep tension on the line so it will stay in the groove in the top of the rudder blade so far it has been working ok for a few months now .I envy you guys with the digital cameras us poorer folk have to scan fuzzy polaroids.

Later Bill