Hello Andy,
I am fortunate enough to be living the answer to your question. The one person I want to study with I have been studying with, apprenticing for, and assisting since 2003.
I tend not to use the term “master” easily as there are many self-proclaimed masters not living their teaching(s).
Aadil Palkhivala is my teacher and while I’ve met many others mentioned, most of them have, at one time or another studied under Aadil.
Aadil’s initial experience with Yoga was prenatal (in the womb) as Iyengar’s work was responsible for his conception. Growing up in Mumbai, at age seven he began his study with BKS Iyengar and at 19 was awarded one of the few Senior Iyengar Teaching Certificates. He holds degrees in physics, math and law. Additionally he is a licensed Naturopath, certified shiatsu and swedish bodyworker, clinical hypnotherapist, and ayurvedic health practitioner recognized by the American Ayurvedic Association.
He has been practicing for over 40 years and has brought together the amazing asana and pranayama of the Iyengar system with the applied philosophy and meditation of Sri Aurobindo expressed through Purna Yoga™.
And while that is all meaningful to one degree or another, it pales in comparison to having a teacher who lives what they teach. You will be hard pressed to find a more steeped, compassionate, focused, master teacher.
We each need to find that teacher who resonates deeply with us. Mastery should be one requisite, but not every teacher is for every student just as not every student is for every teacher.