I found a really good guide to pumping at tigerpumping.com
WARNING: This guide contains some really explicit imagery of cock and balls. So if you're at work or surfing the web while the wife is roaming about the house, you've been warned.
Here is the actual guide:
If the above link doesn't work try the website's link here:
I don't work for this guy nor am I promoting this site, but his pumping guide is the best I've found on the web.
By the way I've been pumping 3 times a week and clamping for 2x10 minute sets twice a week and am seeing permanent girth gains -- quickly.