I'd give it a go for each emotion, and make sure that when you say how you want to feel, put it in positive terms (e.g. like happy instead of "not sad"). As far as frequency, I'd just play around and see what works.
You might want to try one of the new ones, like Happy for no reason. I can't comment because I haven't recieved my copy yet.
anyhow, good luck
George
