I think above 5.5" is big girth. I'm 5.25" and I can see that my girth is a bit thicker than the average cock of my length (6-6.5").

If my penis would magically grow into any size I wanted, I would seriously just stick with 7.25" x 5.75", or something like that. It's just enough to please the size queens while still not breaking the "average girl" in two.