Just for interest. When kent mirror the wing rigg, he goes thourgh each mirrored bone to roll them correctly and make the ...

Just for interest. When kent mirror the wing rigg, he goes thourgh each mirrored bone to roll them correctly and make the rigth wing rigg behave correctly. However, there is a option in the bone IK constraint panel. Setting the "Pole Angle" to 180 degrees does the trick and is way faster.