[Yoda]

At follow through, the left arm fyling wedge stays as it was at impact?

From Left Shoulder to Clubface, the Left Arm Flying Wedge remains in its own
Plane...the Plane of the Left Wrist Cock Motion. Through the Impact Interval
to the end of the Follow-Through, its degree of Roll -- the Sweet Spot
seeking to maintain its in-line condition with the Left Forearm -- is
determined by the Hinge Action employed and its Rhythm:

Horizontal Hinging -- Full Roll (Feels like 'Roll');

Angled Hinging -- Half Roll (Feels like 'No Roll'); or

Vertical Hinging -- No Roll (Feels like 'Reverse Roll').