Hello, usetodancetg, and welcome to CriticalDance. What a wonderful story about Maggie Black! I love the "send the energy through the muscle" instead of locking... I so agree! In my own way, this is what I try to tell my students, too! I feel re-affirmed!
You were fortunate to study with her and she continues to be an inspiration to you. I don't have any recordings or know anyone who has one. Perhaps someone will see this and point you in the right direction... I wonder if any performing arts library collections might have some? Best of luck to you in finding what you are seeking!