I started furling my own leaders after buying Kathy Scotts DVD. I'm using 2 lb flouro and uni thread for my freshwater leaders to a ring. I'm using 4 lb flouro for my saltwater leaders looped to a three way size 10 swivel. I believe the breaking strength of the 4 lb is higher than 12 lbs though. I have broken off some shark in the surf on 14 lb tippet without a problem with the leader breaking. The swivel broke before any probems with my leader on my first set up. I wouldn't worry about the swivel or the ring having any affect on the fish.