I tried Wooly Whispers, cat whiskers, and beaver fur on my curve and the fur was hands down the best. I don't know if they are beaver balls size because they are some I got with the bow that were cut from a hide so they could be a little larger. The fur appeared to have the least effect on bow performance based on bare shafting. On the LB's I typically only need about a half strip of cat whiskers. I like cat whiskers best when they work because I can pick them up just about anywhere when I need them.