There’s a lot of food for thought there for me.
I speak with quite a few anglers, including guides and competitive fly fishermen. Everyone has a POV on what rigs, gear, and flies work for them. Often, the POVs converge, but, just as often, they do not.
For me, I have a 000-wt. for dries. When I nymph, I use a specialty Euro-nymphing rod, which is 11′ and has a sensitive tip to pick up soft takes. Here is my Euro-Nymphing rig these days, tweaked depending on conditions:
Rio’s Euro-Nymph fly line -> nail knot -> 18′ of 20 lb. mono -> blood knot -> 9′ of 0x leader cut back to 7′ -> tippet ring -> 18″ of an inline sighter (12″ of 15 lb. yellow mono and 6″ of 8 lb. orange mono connected via a blood knot to which UV Knot Sense is applied for extra strength) -> tippet ring -> 2′ of 6x fluorocarbon -> tippet ring -> 1′ to 3′ of fluorocarbon (6x to 9x, depending on conditions) -> anchor nymph
(If the water is deep, I attach some tippet and a small nymph to the last tippet ring to work two levels in the water column; if shallow, I attach the trailing nymph behind the Anchor Nymph)
I’ve become a big fan of fluorocarbon since a competitive fly fisherman, who nymphs a ton, recommended it. It sinks much faster than nylon. And, he recommended 6x or 7x, as thinner tippet sinks faster. The sink rate isn’t critical at a shallow river like the Swift, but it is at deeper rivers. You want the nymphs down into the “strike zone” quickly.
Another benefit of fluorocarbon is that it’s very durable. And, when a big trout heads for a log jam or rock, the fluorocarbon holds up well. After landing a 21″ holdover Farmington brown, I checked my tippet. That fluorocarbon took quite a beating on the rocks, but still held up. Whew.
And, on a recent outing at Pittsburg, NH, with high water, 6x fluorocarbon was plenty strong to let me aggressively pull in big fish in, at times, fast white water currents.
This rig works for me. It’s definitely a specialty one, but in a pinch, I can throw a dry fly. I catch many fish with this rig. I’m happy with it.
Everyone has his/her own preferences. It’s one of the magical parts of fly fishing: you get to decide what works best for you.
Edit: Here is a good and short article on this type of rig.