I always try to tweak a little bit of each dial, so I can come up with something unique. Since I'm into realism, go for unique, ultra realism smiles, noticing the small nuances which give it that photographic feel. I think you can make a good smile with 1 dial, but it would be not be unique, in the sense that anyone can turn that one dial. Edit the height of the eyebrows, close the eyes slightly, edit every little point - tip: look at a photograph of someone really smiling, and mimic the natural nuances of the face that gives you the impression of the smile. Smiles can give an entire range of emotions, even fear, worry, and sadness. Just my thoughts. Ben MessianicArt.com