I have been getting less than 2,500 tokens a night over the span of about 3-4 hours on cam an my cam score has managed to raise a little over 1,000 points in just under a month. Some nights it goes up 50-70 points, even on days that I am offline.
I wouldn't worry too much if you have a slow night, but don't forget...if it has been a while since your last tip, you might take a break and come back later or just go ahead and log off for the night...