Use this guide at your own risk. This guide is not supported or approved by the manufacturer. Remote control jets are extremely dangerous and can kill if not flown/built right. I'm providing this guide as my own, non-professional opinion. Always follow the manufacturer's instructions.
Since the SU doesn't have ailerons, the roll is mostly being controlled by taileron.
I used a small mix to create flaperons, but it's mostly to reduce turbulences to the elevator in full flaps - essentially, makes it easier to turn when flaps are down.
108mm pushrod. 9mm arm.
Connect the pushrod to the flap and mark with a tape its path
Flap down at 60mm down position
Transfer the path and up/down positions marks to the cover
Position the servo
Down position
Up position
Roughen the surface and CA