When it comes to fly lines, you have a bewildering number of lines to choose from. Oddly enough, for the most part, just three or four manufacturers in the United States manufacture these hundreds and hundreds of different lines. Most private label lines of rod manufacturers are made by Scientific Anglers and Cortland .
The question is, “Why do we need so many kinds of fly lines?” Quite frankly, we don't, but the manufacturers do because they need to keep selling fly lines to stay in business. In order to accomplish this, special tapers are developed, many of which are slight variations of standard tapers, but given special names with all kinds of hype to try and convince you that you need them. Some are actually useful and do a certain job a bit better than standard, especially if the user is not quite as good a caster as he should be. A bonefish line, for example, is designed to land gently even at a long distance, but a good caster can get a gentle lay-down with a standard taper lines. So, in my opinion, species-specific lines are not really necessary for fly fishing. Both a sea trout and a bluegill can be both caught effectively on a standard taper.
(A bass taper line is quite useful in salt water as it was always used for salt water when salt water fishing with fly rods first started. It worked well as it has a shorter taper with more mass to load the rod quickly for casting when windy.)
Sinking lines are rather newcomers of sorts to fly fishing as they have replaced the split shot on the leader which made casting a bit more difficult.
In short, certain gimmicks should be taken lightly. Use what you have and you think is right and gets the job done. If, however, it does not do what you want that line to do, even after practice sessions, then seek advice by speaking to someone who is knowledgeable in line selection.
Now for leaders – ready made knotless leaders in varying lengths are superb. Knotted leaders are traditional and sold, but you can learn to tie leaders for maximum turnover depending on you casting style. For trout, the water you are fishing will dictate the length, the most popular being nine and twelve feet and many times, fifteen feet. For bass and the sunfish family, delicate turnover is not critical; a four or five foot 12-pound single piece of monofilament and, sometimes, with an added short section of a lighter monofilament of about two to three feet works.
In salt water, however, we often use a similar leader, but in the 15-pound class and about a foot or two longer for the smaller inshore species. When fishing the flats, use a more robust leader material as you will encounter oyster beds and toothy fish which will wear through your leader.
Check your leaders often for wind knots as they considerably reduce the breaking strength of monofilament.
Until next time, keep you fly dry. -- Ed "Soggybottom " Rapisardi