When carping I do a 4' piece of 15lb flouro as my leader and a 4' piece of 1X (~10lb) flouro as the tippet. Reason being, when my fly is stowed on the hook keep while im walking/wading/climbing etc, I have a small bit of fly line peaking out of the tip ring so that when I see a fish I can very quickly be ready to cast and not have to worry about the end of my fly line getting caught in the guides, or my line getting hung up on the ground or sourounding plantlife. Carp only give you one chance to cast generally and Its much easier to do short casts with a shorter leader/tippet. you cant cast unless your fly line is hanging from the rod as the fly line is what you are casting, not the fly
When your out there on the salmon rivers swinging for steel its a different story though. your line is almost always in the water so you dont have the issue I mentioned above.
