I'm not sure how old the technique is, I first came across it in a series of articles in Fly Fishing and Fly Tying by Davie Wooton in the early 1990s. I learned to tie with the threads you describe Byron. The biggest problem was the build up of bulk from them. Modern threads have lead to a tendency for people to use far more thread than is needed. Splitting the thread means a dubbed section can be formed with one pass of thread. Using a dubbing loop leads to three layers of thread to form the same section.

As for wax, I would rather buy my thread unwaxed, then add wax if and when I need it. I know Uni is available unwaxed, but have you ever tried to get any? No one stocks it. I would give the person who decided that I will use waxed thread, whether I want it or not, a good clout round t'ear hole, if I could find them!

Cheers,
A.