I missed out on the Arnold Jacobs era. I was too young. My teacher, Nick Atkinson, studied some with him and passed this knowledge on to me.
Mr Jacobs was THE legendary tubist with the Chicago symphony. He was legendary for his teaching studio too. Here are some masterclass notes, compile by Boston Brass tubist, and teacher, Andrew Hitz. The original source is from Julia Rose, associate principal horn with the Columbus Symphony.
My quickie favourite? “The horn in the hand must be a mirror of your thoughts.” Though with my recent changes in warm ups, this is also a gem: “Match tone qualities when slurring octaves.” And I remember this from my lessons with Nick: “Whether long or short tones, always play with the same quality of tone.”