If you have a Shorb Loop in the tippet end of your furled leaders, I would recommend a Surgeons Loop or Perfection Loop. Makes it a lot eaiser to change tippet when the tippet you are using becomes too short from changing flies. If you use a knot which tightens down on the Shorb Loop, you take the chance of cutting your Shorb Loop when you attempt to cut the old tippet off. Now if you are using furled leaders with the tiny metal rings at the tippet end, you can use any knot you feel comfortable with. Cutting your old tippet off a metal ring will not damage your furled leader.