Great looking flies, Joe C. better watch out or you'll get his job. As for counting the hairs once is enough then you can guess.
I've been tying one for use at nite that uses olive for the throat and tail support with a single black hackle tied flat. body of any color braid and a wing of 10 hairs purple topped with 20 hairs of black. No, I don't count them, just what looks right. Ron