I'd like to mention something i don't think anyone else did and i think it matters , although it might just be one of those old wives tails that us old timers beleive in. For dry flies i always try to use fur/dubbing from "green" pelts , untanned ones , i think the tanning process removes the oils and other natural substances that keep the animal dry. Just something i do and maybe something to consider. If you are a do it yourselfer you can come about many green pelts by various methods not excluding fresh roadkill. Salted and dried but not tanned , befriending a local trapper might be a good idea and you might be able to bargain if they fly fish.