In regard to incidence of the winglet, It can be seen by observation of finished EZ's that were built per plans that the forward /leading edge of the winglet is further outboard than the trailing edge. I remember reading somewhere that this causes the "lift" vector created by the airfoil to be pointed slightly forward. This supposedly causes some forward thrust that partially counteracts the drag caused by the winglet. I don't have my copy of the plans with me, but I remember that they reference measurements from certain parts of the wing, like one of the corners from the aileron cutout, for correctly placing the winglets. I don't really like this because that could mean that any inaccuracy in building the wing could carry through to an inaccuracy in the winglet incidence. One of these days I'm going to go out to the field and carefully measure the angle of an EZ that I have some confidence was built accurately. In addition to canting them outboard, I would think the important thing would be to get them perfectly symmetrical to prevent creating trim drag to correct yaw. If anyone has already measured that incidence angle, I too would ber interested in knowing what it is.
Seth Schlam