@N1684T said in No real gains on anything more than 40-45 minutes of practice.:
But whats a good test of what IS too much pressure?
Endurance. How long are you lasting before you loose fine control of attacking your notes or starting to diminish your tonal quality?
@N1684T said in No real gains on anything more than 40-45 minutes of practice.:
I read one about palming the trumpet, and another about turning the trumpet all the way around while playing a constant note.
Don't do this. This is a high risk procedure to damaging lip muscle.
@N1684T said in No real gains on anything more than 40-45 minutes of practice.:
I have been guilty of using WAY too much pressure when tired... whats a good test?
Your answer is in your question. You feel "tired". This is a sign that is before pain sets it. Being tired is a sing to either cut back considerably or quit for the day (or at least for several hours)
@N1684T said in No real gains on anything more than 40-45 minutes of practice.:
...and actually leaving an impression on the lips...
Leaving an impression on you lips (acutely-which is results in plethora (reddened)) is and advanced sign of muscle blood flow into the area to begin "healing" a stress environment. Now a chronic ring that is silver is a sign of healthy adaptation of the soft tissue and collagen that helps protect your lips.
Collagen is the most available protein in your muscles and ligaments. Collagen is a building block that: 1) promotes skin elasticity; 2) holds together your bones and muscles: 3) protects muscle for excessive strain; 4) provides structure to joints and tendons. Your body produces collagen on a regular basis and will particularly lay down fibers in more areas needing protection (such as that silvery ring around you lip).

@N1684T said in No real gains on anything more than 40-45 minutes of practice.:
I realize this sounds like a silly question, but if i need clarification, others might as well?
Not silly at all. I hope the above segments help clarify.