I am not a viol teacher. I am a student who is just beginning who wishes to learn the rudiments of the tenor and bass. I have a teacher but for the most part I am teaching myself the tenor and bass. This makes having good books important.
I have a variety of books on the viol including books by Ms. Feldman, Ms. Crum and Ms. Bishop. Your books, in my humble opinion, are the best books on the market for learning from the ground up. The compact discs are excellent since you can hear what you are supposed to sound like. And the books simply look good which increases marketability. That is why I have bought so many.
In addition, your method of holding the bow is very different from what I have seen, making it a good addition to learning literature