I get a weekly news letter from
Deneki Outdoors and one of their topics was on fly line construction and how it is put together to achieve different results. I pay attention to this after asking Davy Wotton what was the biggest advance in fly fishing over the last years and he said easily fly line. We typically use weight forward (WF) lines, as they shoot well and give a little more power in the wind than the double taper (DT), but the DT is smoother on the roll and prized by dry fly fishermen for it's fineness. Shoot heads and skagit/spey tend to be for chucking big flies or going the distance, so these work more like throwing a baseball to drag the running line out into deep water than worry about how stealthy they are. Take a look at this section description of your fly line and think about what you are tossing on your own rig this trout season.
In a typical 'weight forward' fly line profile you can expect to see some, or all of the following components…
30 ft Weight: Just what it says, the 30 ft. weight is the weight of the first 30 feet of line measured in 'grains'. It is what dictates the line's appropriate line weight (i.e. 5 wt., 6 wt., and so forth). Why 30 feet? at 30 feet, both weight forward and double taper lines of the same 'line weight should weigh the same, allowing for some consistency when matching lines to rods from varying manufacturers. However, there is an accepted degree of error in line weights, and some lines can vary from 1/2 to even 3/4 of a line size within the same 'weight'. Therefore, knowing the 30 ft. weight can be helpful in matching a line to your specific needs.
Tip: The tip of the fly line is nothing more than a short level section to which the leader is attached. In the past, the tip was used to extend the life of the line by providing a section that can be trimmed after attaching a leader, without cutting into the taper of the fly line. With the popularity of welded loops however, the tip of the fly line is not as important today as it was before, and thus does not need to be as long.
Front Taper: The tapered section connecting the body of the tip to the line, the front taper determines how energy is dissipated from the line to the leader. A long gradual front taper allows for a more delicate and accurate cast, while a short aggressive front taper lends itself to better turnover when casting heavy flies or casting into the wind, although it is less accurate. Choose accordingly.
Belly (Body): The belly, or the body, of the line is the portion of the line with the widest diameter. It is where the majority of the energy is carried throughout the cast. The longer the belly of the line, the greater distance potential. The shorter the belly, the easier it is to load the rod quickly for shorter casts. Choose your belly length based upon the distance you fish most often.
Rear (Back) Taper: The tapered section connecting the belly of the line to the running line. the rear taper is an underrated portion of the fly line. A long rear taper allows for greater control of the fly lilne over longer distance by creating a smooth transfer of energy. A shorter rear taper creates a quicker transition to the thin running line, allowing for greater distances when shooting line. Both have their advantages depending on the type of fishing at hand.
Head: The head of the fly line is the section comprised of the front taper, belly, and rear taper. The length of the head determines the amount of line that can be effectively carried in the air while casting. The longer the head, the longer casting potential. However, more false casts are often necessary to length the amount of line being carried in the air, which may be difficult for some casters. The shorter the head, the less false casts needed to load the rod before shooting line and may be easier for casters of all abilities.
Running Line: The thin, level line comprising the back end of the fly line, the running line provides a low friction segment designed to send the head as far as possible when shooting line using weight forward or shooting taper fly lines. Unless you are planning on boasting casts around the 100 foot range, the length of the running line is not overly important.
I was introduced to the Shop Vac fly a few years back and it has since become one of my staples. A unique fly that is part emerged and part nymph it is an excellent trout fly in a number of situations. It was originally designed for use out west in the Yellowstone area as a Mayfly imitator but I have found it works well and is generic enough, similar to Hares Ears and Pheasant Tails, to work in a multitude of locals. I oversize the bead for the size hook and use tungsten as I want this fly to get down fast near the bottom, after its drift I let it swing and rise to the surface and give it a brief pause at the end, thus fulfilling the role of both a nymph and an emerger utilizing the antron. Simple to tie and effective, I really think you guys will find a lot of utility from this pattern. I fish this pattern in hook sizes ranging from 14-10. 
