Joe Huffman had his fancy schmancy camera with him at the Para USA / Blackwater summer camp. Being a decent SLR, he was able to get some fantastic pictures.
Especially this one
Now, I'm not going to comment on what a gorgeous set of hands those are (hint - they're mine), but I wanted to highlight (a) that this was a cool shot and (b) the Witness Marks that Todd put on our hands. I used Photoshop to darken them up for by this time I had sweat so much they were hard to see (unedited pic can be seen at Joe's place)
Notice how the line from my right thumb meets the mark on my left hand. After a few shots, those lines wouldn't be together, which illustrated how I wasn't gripping properly and sliding around after a few shots.
Harder to notice is the line on my right hand which indicates where the center of the pistol goes. A better picture of that mark can be seen here. I didn't have too much problem with the pistol going off center, but once or twice after finishing a round of firing, I did notice it was askew.
I personally think this was the most beneficial teaching moment from the whole course. This one grip change tightened my groupings up and sped up the time to get back on target. The position my left hand had to take was uncomfortable at first, but once I got used to it, nothing else feels natural.
I've been dry firing every night with the Glock 29. I can grip it almost identically with the exception that the G29's grip is way shorter and I have to 'tea cup' it slightly with my pinky. But using this grip, I come up to the target very, very fast. I cannot wait to hit the range again to see how much of this I retained!