I guess I should give my leader formulas ...
Long fine taper or light Spey line leader:
15ft - 7ft of #15, 4ft of #12, 4ft of #10 or #8
20ft - 10ft of #15, 6ft of #12, 4ft of #10 or #8
Stout taper or heavy Spey line leader:
15ft - 7ft of #20, 4ft of #15, 4ft of #12 or #10
20ft - 10ft of #20, 6ft of #12, 4ft of #12 or #10
I usually tie these with Maxima Ultra Green. I sometimes substitute with Maxima Chameleon for windy condition, just really difficult to find the Chameleon in my area.
Word of caution: if you plan to use florocarbon, do not use load leg cinching knots, stick with Double and Triple Surgeons Knots
I'm not going to explain this here. There are many old threads discussing the issues. Search for peter-sc, you'll find more than you want to know
The fine taper leaders are for lines like the old XLT 6/7 and 7/8, or I.G Spey lines up to 9/10. Snowbee 2D's and 3D's fall into that category too. Same with the Beulah Aero Head lines up to 8/9.
I use the stout taper formula for everything else. I.G lines to 11/12, all Drury Impacts and Mackenzie lines. The DT's love the 20ft version and the heavier Gaelforce 15M Extended Spey Heads in #9 and #10 are a match made in heaven with the 15ft version.
For skating heavy hackled flies, I like the 20ft versions of both. Waking flies, I cut off two feet from the butt on the 15ft versions.
When I reference "Long Thin Leader" in my posts, these are the leaders I'm speaking of. The "Fine Taper" leaders will turn over my #1/0 heavy vintage irons and up to a McNeese #2 iron. The "Stout Taper" leader will turn over Dee and Spey flies up to #4/0 Code Irons, no questions asked. These "Long Thin Leaders" will allow my heavy irons to sink quickly. I feel I get a deep, long plane swing ... more than a Type 3 tip, but not more than a Type 6, somewhere in between.