Triangle your legs. Look down. The triangular space you just made is how big your triangle is. That space stays the same no matter what angle you take relative to your opponent. It's a constant.
What changes the pressure then becomes how much of your opponent you have trapped in that constant sized space.
When you are square with your opponent, you naturally trap more of his shoulder area in the space. This is because when you are square, your triangle naturally cuts across his body in a diagonal way.
Cutting straight across his neck is always a shorter distance. When you angle off to do stomp/curl, you are putting less shoulder in there by going across that shorter distance. That's why the angling tip of "hide the shoulder" works.
There is a certain tradeoff range in which you gain more from the extra muscle power the stomp/curl position gives you than you lose from making the triangle looser. Making that tradeoff is why stomp/curl works for a lot of people.
But if your triangle is already loose at the square stage, you fall outside of that range once you make the angle. You take something already loose and trap LESS of your opponent in the fixed space (i.e. trapping just his neck and minimizing the shoulder by making the angle). That ends up being a problem if you are tall.
