I started tying flies this winter. I watched some videos and tied some flies. Now I want to use some beads and barbells eyes, so I went to the store to get some beads and barbell eyes. Now here is my problem:Hooks are sold by size 20,18,16, ... and beads and eyes are fractional size. So how do you match them up? How do know that the bead will slide over the barb of the hook? How about the barbell eyes how do you size those to the hooks? Any info will help. Thank you