Ripping cards after a suckout is very tempting. [img]/images/graemlins/grin.gif[/img] Seriously card tearing is great training and bm casinos are a great source of used cards for tearing practice.
I train grip 6 days a week. But in the beginning you may only want to train 3 days a week. You can seriously over train. I stuffed my left hand bending a box wrench and the tendon damage takes a long time to heal.
Here is a training programme that was written by one of the Gripboard guys who is a COC on the 3 and 4.
Link1
Link2
If the site doesn't work (It's a bit erratic) PM me and I'll send you the pages since I have them on file.
This kinda training assumes that you have more than one gripper though.
At a later point you might want to try something similar to what you mentioned regarding closing the gripper every hour during the course of the day. This is similar to Pavel's GTG training. I have my 2 next to my computer and some days I close it once every hour and hold for 10 secs. That gives quite a different crush workout and shocks the body a bit.
However at the minute you need to build a solid foundation of hand strength and that's what the linked training programmes are about.
How are you finding the kettlebell training in general? It should make for some good allround conditioning. Seriously though try the sledge hammer levering thing it's very addictive and builds great forearms.