The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
Cut off the loop, tie a neat nail knot, carefully coat knot with Loon "Knot Sense" tapering on either end and either cure with a UV light or take it outside in the bright sun light for about 30 seconds. This slips through the guides effortlessly.
I'm playing devil's advocate here, but what about leader changes on-stream, say going from a 12 or 14' dry leader to a 7' streamer or nymph setup?
is to nail knot 8" of 25lb butt section to your fly line. Attach a tippet ring to that short piece of butt section. Now when you do a leader change you just attach your leader to the tippet ring. The 2.00mm tippet rings are not any bigger than a conventional blood knot, this creates ease of leader change, as well as keeping the leader to fly line connection streamlined to go through guides easily. I like this set up because I go from a 30' contact nymph leader to a conventional leader often, I dont like loops, and I dont necessarily enjoy tying blood knots, so this is the approach I use.