Here are some more grip training links:
Body Results
Steve Gardner
Rugged Mag
The last link has an interesting thumb exercise using a cable setup. This may adapt well to substituting the cable/weight stack with a Jumpstretch band.
Hand Wrist Grip and Forearm Strength Training. Using Ironmind Captains of Crush Grippers , blobs and home made stuff. This BLOG is the rantings of a lunatic. His writings are opinion. Read at your own peril. But you will find some good training info. No fictional hand bullshit here. This is not a "grip parody" site. No Quarter Given. A Fucking Blob is a Fucking Blob - except for York "Legacy's" ;) Fuck Baraban.