I was once told by a conductor who was doing the premiere of one of my pieces: “It doesn’t matter what you put on paper. String players will bow when they want to. Wind players will breathe when they want to. Don’t sweat how you write it. They’ll ignore it in any event, and so will I.”
One thing I often do in long phrases for solo wind instruments such as oboe or clarinet is to break the phrase up between the woodwind pair. To the listener it all sounds like one instrument, and the performers love me for looking out for them, and they like making it sound like a single solo as well.
In my experience as a student with Tuba through high school, Tuba takes a ton more air for the lowest notes, versus minor comfortable effort for the same length at mid range. I suppose it’s an extreme, but there was a somewhat similar relationship for me with playing bari-sax. Loose lip equals a comparative flood of air…