Really? So the T can't set up with the outside leg a bit further back, giving him a flatter facing towards the DE, forcing the DE to decide to go deep...in which case you just let his momentum take him beyond the QB, or try to undercut...in which case you have angle on his outside shoulder and can power him into the scrum?
You are correct that it is about the angles, but you are incorrect in that there are multiple ways to handle each type of set. In fact, you would play base as if you were playing a wide 9 defensive end. In wide 9, the DE is way outside of the T outside shoulder. The goal is to 'flatten' the rush (what you are saying is a goal of the T and a shallow drop). The T, in order to counter the wide 9, sets at an outside 45 angle, facing up on the DE...again, forcing a decision. Same blocking principle.
