Wilmer,
I hope you don’t take offense when I refer to the gentleman you speak of as “old school”… or maybe I should just say the “older school”

… at any rate…
You made an excellent point when you mentioned that much of the playing was “all on Bb”…
Don’t get me wrong… if playing a passage on a higher instrument makes my life easier, I’m all for it…
But lately I’ve really come to appreciate the fact that these guys (and I’m sure you too) played the Bb trumpet on almost all the orchestral literature.
Now of course, some of these folks were so gifted that playing on a Bb, C, X, Y or Z would not make a difference… but it takes playing a few tough excerpts on the Bb to really appreciate the command these guys had of the Bb horn.
I was reading an interview on the most recent ITG journal … Kadarebek interviewing David Zauder… many comments there about him only playing the Bb at Cleveland.
My first teacher, Gilbert Mitchell also recalls his many years in orchestras only playing the Bb.
Thanks for mentioning it. It deserves some attention.
Rogerio