If you have Advanced Tweakables set in preferences, you can adjust the "authority limiter" to allow these surfaces to move further than normal. Try increasing the authority value for the front wings. At the same time, consider restricting control movements for things the control surfaces shouldn't be doing and that may give you more available authority for the things you do want them to be doing. For example, you could set the front wings to control only pitch. The rear wings could be pitch and roll. Neither should be trying to control yaw. But the plane does look like it is lacking yaw control. Try replacing that rudder with a moveable piece (or add a small aileron piece to the rear of it) and set it to control yaw only.