Denny Rickards in Fly-Fishing Stillwaters says, "The purpose of a fly is to match or simulate a particular insect (food source). the retrieve brings life to the fly, but the fly line is the vehicle that makes it happen. From an angling viewpoint, the purpose of any fly line is to hold your fly at the depth fish are feeding for as long as possible." "When trout feed on ascending insects, a floating or sinktip line is a good choice. A full-sinking line is a better choice, however, when fish are feeding on leeches, scuds, dragonfly nymphs or baitfish. These food sources are found either moving horizontally, and on or near bottom where they are most effectively imitated with retrieves possible only with full-sinking lines."
For steelhead, I use floating or sinktip lines, almost exclusively. The one exception might be suspended fish near tidewater where full-sink lines can be an advantage. That would be true for suspended salmon, as well.
solo- well designed sinktips do not hinge either. That has been a problem in the past when there was too big a change in density between the floating and sink parts of the line or tip. For example, if you have a T14 tip attached to eight weight belly, you will get a bad hinge. Attached to 12 Wt or larger belly it works fine. Actually, I think Ed Ward makes it work attached to 11 Wt for some of the lighter rods like the Sage 7136.
Practice is about increasing your repertoire of ways to recover from your mistakes. Joann C. Gutin