Hi Gene, I'll share my thoughts about the use of swivels, but understand I am in no way suggesting that my way of thought about this method is the, "end all" method. It's just what I have evolved too with experimentation over time. From comments on a similar thread here recently, it's clear that other successful vertical presentation anglers employee slightly different methods.
For me, when I fish vertical my highest priority is to see the bite. Not all bites result in a bobber plunging for the depths! In fact (as observed in gin clear water), sometimes fish will, "lick", "taste", "test" the pattern by swimming up to it, stopping, swimming around the pattern, then sometimes suck it in, then spit it right back out only to continue the process over and over until either losing interest, or deciding to eat it. The best chance of hooking fish that "work" your pattern is to visually see that it's happening in the first place.
So, with the above paragraph in mind, I strive to build my setup to give me the best chance of detection from those light biting fish. My thought is that while fishing vertical the angler has the best chance of detecting the bite if the leader is held as taut, and vertical as possible. Any coiling affect in the leader will lead to light bites not being seen by the angler. If there is any current (and there is in some "stillwater" situations), or when fishing perpendicular to the wind then the leader and pattern are pulled at an angle, and bounced around with inconsistent slack created in the leader. The best chance of keeping the leader taut, and as close to vertical as possible is by weighting the leader. Swivels are a clean way of adding the weight. Swivels allow good tie points, are strong and durable for their size, and allow a method of creating a leader system that is modular depending on the knots you build your system with.
I don't choose to build as much weight as I could into my patterns. My feeling is the fish are more likely to hold onto the pattern longer if the pattern is as light as possible, yet perform like I need them to. Some weight is of course necessary to keep the tippet taut.
As for the bobber, (indicator if you like) I like the bobber to be small enough to absorb some of the wave action and dampen the bounce at the pattern when the chop gets a little tall. I also feel that on a good take the fish are less likely to let go of the pattern as quickly (were talking nano-seconds) with less resistance felt by pulling the bobber under. In other words, giving me the best chance to react and strike on the take.
So here is my summary of a setup that works well for ME. Bobber just large enough to float my rigging but that rides low in the water. Heavy swivel to keep the main length of leader taut & vertical. Brass bead patterns (not tungsten & lead) to keep the patterns lighter and more animated in small chop.
I can't prove any of what I say to be an absolute fact. I do what I do based on much experimentation and what works for me, nothing more.
Here is the type swivel I like to use. If we are counting respected anglers who also use this style swivel you can count Chan as one. Of course, Chan, Rowley, and others in the industry have to take care of the sponsors in their media work, but what they actually use may be a different story.
If I had to guess, I would say the great majority of anglers using swivels in their leader setups DO NOT use as heavy of swivels as I do. Fair enough?
Rolling Barrel Swivel
http://p-line.com/tackle/swivels/hi-speed-rolling-trebel
Bye the way Gene, since you are an Oregonian, know that the use of swivels are illegal in Oregon's "Fly Fishing Only" waters. I called and discussed this with a State Trooper. He consulted with ODFW, & other game enforcement then called me back with the answer that swivels would be against the law in Fly Fishing Only waters.
Randy