[6bmike]

If one is using a truly neutral grip, where should the line between the thumbs and the forefingers point? To the right shoulder? To the sternum? or somewhere else?

I played yesterday with the lines pointing to my sternum, almost in the center of my body, and hit the ball consistently straight. Am I losing power not using a stronger grip?

It's not so much about where that line points, but about Flying Wedge alignments and Hinge Action/Rhythm. The grip should compliment whether you pull or push into impact, the amount of Roll from acc#3, etc. Just part of the Educated Hands. Grip is 'found' at impact Fix.

Shaft lies under the heel across the palm for the left hand and in the cup of the right hand. This allows each hand to move in its plane of influence. There are strong and weak versions of each grip type. 10-2 goes from A-G. It is all about Hands to Plane. Power is built in each type.

Sorry for the non-answer but once you learn what you need you are that much better.