I doubt that I will help anybody understand triangle theory. It is hard to teach and took me months to begin to grasp. Thus, your triangle. The larger angle 1 is tends to follow how much grappling a person has done. Now this doesn't mean only grapplers do this.
Heavier people do it also.
It provides more stability in the stance. It is a bit premature to call this an absolute, but I am still observing. It is very nice.