1-2 grams is ideal...
I was taking 1 gram (2 caps) of SNS CoP with my MaxIntense (also has CoP) not too long ago. As well as 2 grams (4 caps) with other pre that did not contain CoP. I did noticed a slight increase in endurance and recovery.
If I could afford it, I definite would make it a staple so that I can get the 1-2g in during my workouts.