BP I practised mostly in guitar keys. F# B A E. Now just getting back into things after not doing any playing for a 4 months except for our video recordings I am back to that focus. Tone control I find comes best for me from long tones. Nowadays I will be working on something and hand on a note somewhere in the phrase for several seconds. Weird but I get a better sense of my intonation and tone rather than setting out with tone in mind. I suspect if I don’t like what I hear I will end up back at formal long tone overtone 15 minute a day routine.