I've got an old book from the 80's called "the way they play." It was one of a series of maybe 15 or more books on major artists at the time.
There's a full article and interview on Azarkhin, as well as pictures of him and his bow. His (German) bow had weights taped at the tip and middle of the bow, and he had some kind of thumb lever mechanism that would change the tension of the hair when he pressed it. Wild stuff.
The book's in storage now, but I could dig it out. I think scanning it would violate copyright laws, so not sure how to share this info.
Here's the book for sale online from some rare bookseller. Steep price!
http://antiqbook.com/boox/paw/1004844.shtml