<font size="4">i have an UltraSport 60 that has the same setup.  Nothing wrong with that.  Nylon  into wood is the same way mine is held on. The way that it is held on once you tighten the screws snug, it will knock the wing off, rather than bust the wing when it touches the ground, etc.    I assure you that whatever you can dish out in the air, that the setup you have will NOT fail.  My plane has done violent snap rolls, level to straight up, and everything else, and has not loosened a bit.   The plane is built simular to mine, I believe.  (someone correct me if I'm wrong)  You will like the plane.  </font>