I assume for trolling...Never use snap swivels IMHO. 12' +/-, 80 to 130# Flouro crimped to pin rig, yes the spring is fine with a skirt, wired or rubber band if naked. Spro windon at the other end of leader. tied to mainline with whatever knot you feel most confident. Depending on my mood either cinch (not improved) or Uni ...again IMHO