I am following WindWorks and do not think you have to do it the Porter way. This will work for some (or many) and Porter cautions that it can be done wrong by pinching the center.
When I do the peel off I get air and I am quite certain I am not using mouthpiece pressure to change notes. However, when I play high D (above staff or stave) and peel off the center of my lips collapse into a buzz that is a low F (first space). However, I cannot go from a buzz to a note. I set embouchure, tongue, and jaw to the shape I know that will get the note I want and it is there. Right now that is up to a D above the staff (stave). I can play E above the D, I just do not feel I own the note. I can play the scale up to high G, but that note is a little it and high F are not ready for “prime time”.
I am currently working on the Allegro E and Presto F. I review one note and work on the practice charts and then I work on the beginning of the next note. I am pretty sure I could skip to Presto G or maybe A, but I am sticking with the process. I feel like it is building up to a more dynamic range bit by bit.
I used to play with a tight center and mouthpiece pressure. Now, I do not and have a better sounding, dynamic range using WindWorks and no pain.