To be clear, I'm no expert on Marcel Moyse, but I've hung around with a lot of flutists, and I respect their approach to tone. Discussions of which usually wind up pointing to Marcel Moyse, or to one of his influential students like William Bennett or Trevor Wye. Not everything in Moyse's or Wye's books is applicable to the clarinet, but there are plenty of nuggets for us.
The tone study has been a mainstay of my practicing and teaching for nearly 30 years, although listening to the edit I can tell I need to record myself more, not just when I make videos. My own intonation has gotten a bit wonky; you can bet I'll be working on that.
If you're interested in music at Duquesne University, you can reach me by going to www.duq.edu and searching on my name.