[O.B.Left]

Glad you liked it Donn.

Here's a few other things to consider...

-take a look at where the back of your left hand points when you're standing in a relaxed manner with your arms hanging at your sides. You elbows are aligned so that your arms naturally fold in the direction of your mouth and so the back of the left is not aligned at 90 degrees to your golf foot line. Its "Turned". This is really the true "vertical" though not literally vertical at 90 degrees to the foot line or ground or whatever. This is the actual "neutral" left hand grip. Neutral anatomically.

-Hogan fought a snap hook.

-some photos of Hogan show a slightly stronger left hand grip than he advertised. You can have the left thumb on top and have a slightly turned left hand after all.

-assuming a straight away shot, a square plane line and a club shaft that travels an inclined plane the clubhead will approach the ball from inside to out. The line on the ground that corresponds to this is the Angle of Approach. So, if you really wanted to grip the club so that the back of the left hand pointed down the delivery path of the clubhead you'd have to turn it on the club so it was at right angles to the Angle of Approach..........which gets it back to about where it is when your standing with your arms hanging naturally at your sides.

-take a look at Macdonald drills number 10 and 11. The position that is illustrated there shows how much the turning Pivot, Zone 1 can open the club face. Imagine if from that position he were to extend his arms out in a normal golf like fashion......he'd be aligned for Horizontal Hinging with out any independent left arm rotation as you mention.

-Horizontal Hinging has the "Vertical" (but not literally vertical) left wrist maintain its perpendicular relationship to the Horizontal Basic Plane , the ground. Angled Hinging would see it maintain it perpendicular relationship to the Inclined Plane.

-the "cup" in the left hand at Top is also a function of grip type. With the club in just your left hand, from your address position cock your left hand directly up towards the ceiling in a hammering like motion. Dont allow your left forearm to turn just cock the hand up. This is the Plane of the Left Hand Wrist Cock, the Left Forearm Flying Wedge in isolation. Notice how this On Plane left hand wrist cock will have more "cup" appear the stronger the left hand grip. A 10-2-B grip will appear relatively flat when uncocked but slightly cupped when cocked. This "cup" is the new "Flat" Left wrist of your chosen grip type, in its fully cocked position. Its not literally flat but rather "geometrically flat". Depending on grip type the golfer who achieves literally flat has often done so by breaking the plane of his left hand wrist cock. Some pros break the plane of the left hand wrist cock intentionally when hitting flop shots or similar by adding more "cup" at Top.

-Here's another way to think of the "cup"........ ideally the palm of the left hand lays flat against the Inclined Plane at Top. But the left arm is above the Inclined Plane assuming any Accumulator #3 Angle as for full shots which means you've got some cup. Literally flat at Top is often off plane.

In short what worked for Mr Hogan does not necessarily work for the rest of us. Some of his methodology might be considered as compensations. If so, though he was a golfing god, his compensations will only work for those of us who have a similar need for them. Id kill for his swing though so believe me, I understand where you're coming from. I worship the guy actually. Fifteen years ago I had the grip, the cup at Top, the alpaca sweater the cap and sometimes when things were going really well even the limp.