Patrick... When buying calf tail, I pick thru what's on the rack to find the longest and straightest fur on the tails that I can find; and for white tails, I look for the snowiest of white (and sometimes, I'll look for transluscence in a tail...similar to polar bear). As for what percentage becomes waste, after my pickiness, I would say about 40-45% hits the waste bucket. I like to tie with squirrel, fox tail, and calf tail...I prefer it over buck tail, but I will tie with that if I get the urge. I mainly tie steelhead flies, hence the longer hair fibers. Different furs react differently when exposed to water and current.