It has taken me awhile, and I apologize to those who have been waiting, to post some different shots of the grip. Attempting to teach someone a new grip through words and pictures alone is very challenging. I hope these additional pictures help.
The first picture is taken from above to show you how much the grip in the left hand sits in the fingers. While the heel pad sits on the top of the grip, the thumb pad does not in fact make contact with the club. I could very easily run a finger underneath the thumb pad. There is absolutely no hand or thumb pressure at all.
You can also notice how the heel pad of the right hand sits on the middle, ring and pinkie fingers of the left hand. The finger nails of the middle and ring are covered up. No part of the right hand is in contact with the club. To refresh, if the grip is truly in the fingers, you can control the putter effectively with no tension in your hands, arms or shoulders. You can let it swing itself, which is the topic of an upcoming post.
In the other picture, you can see the finished product. One of the reasons I touch my forefingers is that I want my hands to feel as one. When the right heel pad covers two of the left fingers, the right arm will be less prone to straighten because the hands are not split apart. If the right arm is straight, it can become too heavy and put undue downward pressure on the putter.
Choosing the correct size of the grip is very important. If the hands are too big for the grip, they will feel too smashed together and the right hand will feel like it is falling off the club. If the grip is too big, it will be very difficult to get the left hand grip in the fingers. The heel pad won't stay on top without feeling overly stretched and tense.
As a reference, I wear a Cadet Medium glove and my grip is the Golf Pride Tour Classic. It would be a Mid Size. For those who have large hands, Tiger Shark makes a very good oversized grip. For small hands, the Golf Pride Pro Only works great.
For more on the grip, see my earlier post. Grip to me is critical. The only person I teach who does not grip the putter this way is my best player, Zach Johnson. Believe me, the irony is not lost on me! While we make a few adjustments to work around his left hand being in the palm (see earlier post on Golf Digest article), Zach is most comfortable with his grip. Every person that comes to me has a choice to grip it in the palm or fingers; no one so far has chosen the palm. I would encourage you to experiment with both. I think you will notice the stability of the left hand when it is in the fingers and the pad is on top.

Pat, thanks for all your helpful information.
You said, "no part of the right hand is in contact with the club." But in the second photo it sure looks to me like the right thumb as well as three fingers are on the club.
If you have time to clarify it would be much appreciated.
Thanks,
Andy
Posted by: Andy | July 12, 2009 at 07:06 PM
I think he means no part of the right palm, as in, the putter is in the fingers instead of the hands.
Posted by: Kwang | September 08, 2009 at 12:17 AM