I do not feel like I was "on" and I don't get unusually good pumps when I'm on Natadrol. I feel just normal. Appetite increases, weights feel lighter and weight increases faster than usually. It kicks in quite fast but everybody reacts differently.
I'd say 8 caps per day is good for your weight. Take it at least 5 weeks, preferably more. Three bottles would last 6-7 weeks and that would be good length of cycle.