Hello Scott - Taking the book literally is probably almost as bad as looking at me performing the moves on the video back in 1988. It's not a matter of being wrong and regardless of what the book says I can tell you this; My Grandfather never told me to hold the club handle with my fingers and my positions of the swing in the video were more incorrect than correct. The book and video needed better editing.
I know what he says about the right thumb and forefinger, Hogan had similar thoughts on this but the reality of this swing makes it imperative that one have more holding pressure in the palms and use the right thumb and forefinger for directional purposes only. When you hold tight with the fingers the palms are loose making the wrists loose. During the backswing the right hand thumb is rolling or pushing the right thumb down so the hands do not flatten out. This is a real problem for golfers trying this swing. Their grip becomes flat at the top of the backswing thus causing shanks and the only way to keep the club hooded or closed at the top of the backswing is to have the right forefinger knuckle pointing right into your shoulder blade and you won't achieve this without the right palm pressing into the left hand to the club and the left hand holding tightly (not with the fingers but with the palms).
Also it is impossible to hold the club handle diagonally from the tip of the forefinger to the butt of the palm by squeezing the fingers tightly. Moreover holding the club with the fingers leads to the handle lining up with the finger joints similar to a baseball bat grip and we all know that baseball hitters use a whole lot of wrists. Grip with the fingers and lose the wrists. Grip with the palms and the wrists and fingers follow in step like a well scored waltz.
Watch my 1st YouTube video - and you'll see where I place the club. A diagonal line forces the fingers to expand along the club handle.