60% of toal desired leader is butt section (30lbtest) 20% of total leader lenght is mid section(20Lb test) 20% of total leader length is tippet( 12lb test)
For a 7.5 foot leader: butt would be 4.5 feet,mid section 1.5 feet & tippet 1.5 feet
For a 9 foot leader: butt would be 5.4 feet mid section would be 1.8 feet and tippet would be 1.8 feet
We fish with floating lines and fish crayfish or streamers on the bottom so we fished 9 foot leaders to help get down to the bottom .
If you are fishing on top a 7.5 leader is appropriate
Tie your flies on with a non slip mono loop to give your fly more movement
For a 4 or 5wt taper from 20lb to 12 lb to 6 or 8 lb test