Mike, it depends on what I'm using and what I want to tie. On my Bright Spey I've tied up for a couple of swaps, I use seal in a dubbing loop. In this swap, I used some stuff I found at Sportsman's Warehouse called SLF Enhancer. I'm not sure if this is really SLF or some other synthetic. The package says it's distributed by Wapsi. The nice thing is all the fibers are about the same length (1/2" - 3/4"). I premake the dubbing brushes by hand using my dubbing block (usually while I watch TV; I feel I'm multitasking). I use some thin wire (like the smallest size Uni-Thread wire). My brushes tend to be just over a foot long. I've found I can get four flies out of three dubbing brushes. I wrap the brush tightly forward, sweeping back the fibers after ever turn I take. This allows me to get a tight body full of fibers. So the body should be nearly indestructible (I wouldn't recommend using for pike or bluefish). Once the brushes are done, it doesn't really take long to tie this pattern if all the other materials are all laid out. Hope this helps.