The "7-heads and half" has to be taken with a grain of salt because it doesn't account for hair, clothes, and assumes a horizontal angle of view.
But keep in mind that larger head/body ratio hints at a teen or child character (or SD style), and this can be contrary to what you try to represent.
About the pose, you can study how comics (or manga) draw characters in suits. These mediums tend to be extremely dynamic, it's easier to 'get' the extreme movements that they show, and apply a much more subtle thing in your drawings.
Another reference is the "Contrapposto" pose : It's very worthy to study and practice, because the resulting characters are less symmetric, much more interesting to draw and look at.
(There's lots of nude statues if you google image for it, here's a clothed example with a tutorial video :
http://www.universityoffashion.com/lessons/male-contrapposto-pose/ )