Other builders have had issues with the rudder fairing into the vertical stabalizer due to the free length of skin beyond the vert stab spar becoming wavy. I noted some builders placed formers between the skins to resolve this. I chose to add 3 layers of carbon fiber to do the job of maintaining a true straight fairing . after laying up the carbon , I sandwiched it with staight boards and clamped it unti cured very straight and true result.
