I have tried all the Powell style headjoints, but what I may perceive as having the biggest sound and so on, you may have an entirely different opinion on it. What I would recommend is if you are able, try each cut in a blind test and go from there. If you start analyzing the shape or cut of the headjoints too much it can make the process of choosing one that much harder. They can not be labeled or described entirely as we all play differently and will all sound differently when given the same headjoint to play.
It doesn't mean much, but my favorite style was the Venti. Good luck with it!