I take 4 per day (2 in the a.m. and 2 in the p.m.) and I'm OK. I am also very small. My doc said that ideally I should take 3 doses per day unless I found that 2 was enough.
I think if you find you need to take more, go ahead and take ONE extra CAPLET at a time until you find a level that works. When I was adjusting from 2 caps upward I always moved up by one cap at a time for about a week.