[O.B.Left]

HK is saying that the Back of the Left Hand (With a Flat Left Wrist) is on the Left Arm Wedge Plane and the Back of the Right Hand is on the Inclined Plane.

In regard to 6-B-3-O-1, I take it to mean that the plane of the RFFW is the plane of the right wrist bend, at right angles to the plane of the LAFW. So not the inclined plane, all the time anyways, at address and impact yes but elsewhere no.

So with your arms extended in front of you, parallel to the ground, the LAFW plane is vertical to the ground and the plane of the RAFW is horizontal (as in yodas table photo). When dropped down onto the inclined plane the plane of the RAFW will be on (or part) of the inclined plane but only until startup begins. As the left wrist turns to plane so does the plane of the RAFW turn under the inclined plane.