I vaguely recall someone posting, perhaps on this forum somewhere, that Maynard had 2 primary grips he used on tour -- one being the traditional Maynard "power pistol grip", and the other being very similar. I didn't realize the evolution of his grip on the Monette setup.

That was during play, but he did hold the trumpet really weird, several times in a row, at a clinic I saw him give at North Texas in 1992 (1991?). He was talking about breathing, so was talking with his hands a lot. He kept sitting his horn down. When he picked it up, he held it in his left-hand only, all fingers below the the 3rd valve slide -- and was holding his right hand up to "visualize" what his diaphragm was doing. He must have put it down and picked it up again at least a dozen times, gripping it in this same 'barely-grip' each time. Granted, he wasn't "playing a tune"... but he was ripping dubbas, holding the trumpet with pretty much only his left index finger and thumb wrapped around the bottom valve caps.

That was the good... now the bad and ugly... I was taught, as Dave said, to hold the traditional "ring finger over 3rd valve slide, only pinky under" when I was young. My long-time teacher, Larry Skinner, and my couple-of lessons teacher, Galen Jeter, both told me to slide down and put 2 fingers below the 3rd valve slide, and use my middle finger for the slide ring. Larry told me that if I must use too much pressure to play high (which I did), it was better coming from the bottom of the horn than the top -- get my right pinky out of the octave key, and use my left hand to pull in and down as my octave key...