Can't find the RMRC Strix Stratosurfer flap kit anywhere? Here are control arms that will fit. just find some arms, clevises (clevi????) and servos. I had everything else from previous crashes, I mean builds.
You can use 2mm screws, or a standard micro servo mounting screws will work. I tried to replicate the aileron control arm as close as possible. Print in ABS for max strength. I used PET, but I have not flown the airplane yet (04/03/2019) it's still coooooold
eSun (any) PET or ABS
i printed with supports for the overhang on the actual control arm. it may not be necessary
use 2mm screws or micro servo mounting screws to secure to wing