Over two years... I believe....
Essentially, from my portrait posing research, I've got the posing boiled down to 7 basic rules to posing a good portrait...
1. Make sure the face is never turned away from the main light.
2. Make sure the shoulders, waist, and hips are never squared off to the camera.
3. Make sure the arms are never posed in contact with the side of the body.
4. Make sure the chin is never lowered to a point where it diminishes the catch lights in the eyes from the main light.
5. Make sure the spine never forms a vertical line and the shoulders never form a horizontal line in the frame.
6. Make sure to never have an expression on YOUR face you don't want to have on the client's face in the portrait.
7. Women tend to greatly subconsciously respond well to portraits of men in which the head is tilted fairly sharply... HOWEVER - Never tip a man's head to the high (feminine) shoulder as he will look feminine. Women's heads can be tipped toward either shoulder, but the feminine shoulder is more appealing.
There are a few other tricks for making subjects look slimmer and what not, but those seem to be the basic rules that are followed in the best portraits...
Now, some people may like the gay head tilit... but it's pretty obvious what it does...