Hi Logan,
Glad if what we posted helped.
I was pinching off my upper register too–my range was G above the staff, practically.
I wouldn’t say that putting more lip tissue into the MP helps relieve the pressure.
I would say that engaging the aperture corners surrounding the aperture, tightening only as much as necessary as we ascend with the middle of the lips relaxed changes pitch without much/ excessive pressure.
The key for me was focusing on passive air released into the mp/horn and experimenting with engaging the aperture corners and realizing how little effort was needed to change pitch (especially middle C to E on the staff). That helped me hone in on the movement(s) needed to change pitch.
And focusing on how little difference there was between G below the staff, G on the staff and G above the staff, etc.
Along with the fact that less air is required the higher we ascend and the harmonics are closer together the higher we go.
I do believe that less is more and the more natural feeling the better; however, we must remember that what weve been doing hasnt been working so what feels natural at first might not be optimal/efficient.