The Builders manual advises that the rudder is possibly the most difficult part to build on this aircraft i would have to disagree. While the tip rib wasnt all that difficult - there is only a short sentence describing it. Beyond that sentence there is only a plan view of it in the plans - no elevations . I generally get a mental image , kind of a mental 3 D rendering of a piece or part Im to make . This piece left me mentally challenged - I just could not visualize how the skin would form this complex 3D shape without bucking / buckling . The end result wont be seen until the lower skin is glued - but through the process I continually checked the form with ply test wraps - at this point I believe skining it will work fine .