We Only Run Flys Behind Our Spin Doctors And Most All Have Leaders To Tie Them To The Sd, Then Our Leader From The Diver To The Sd is 24 Inch For An 8inch Sd And 30 FOR a 10 inch Sd, And That Leader Is 30Lb Seaguar, The Lead Length We got From The LOU Tackle Forum, It Is A Must Read For Salmon Fishing.