Here is an idea. Not sure it is a good one. Lay a long batten on the crown of the wing and draw a line (felt pen). Then do the same on the old wing. At stations (every 6" or so) measure the old wing from the line to inner edge and transfer this measurement to new wing. Use a carpenters square to get the measurement from the reference line to edge. A boat shop could probably make a long batten that would be flexible and straight.
