Thanks guys, truly appreciate all the very kind comments.
fishabuoy -- Yep, it was tied for Delta LMBs this summer. No, I don't apply glue or anything else to the fly before fishing it and the collar does have some flex to it. When I fish it, I expect the water to travel up the head and hit that collar, thus forcing the fly down. They've always worked as intended, so I've never thought to do them any differently.
troutbuster -- Funny you should ask about why I trim the collar down almost to the marabou, as you're not the 1st person to ask. To be frank, I don't have a real reason other than I'm self-taught and that's the way I've always tied them. With that said, though, it has occurred to me in the past that this provides less soaked hair and related weight to carry in the air; perhaps fewer opportunities for water to "wick" into the hair, thus soaking it sooner; and I've thought it made the fly a little less wind-resistant for easier casting. Since I've never tied them any other way, these only amount to mere speculations on my part, though, sorry.
skidoosh -- The fly is tied on a size 2/0 Gamakatsu B10S hook and is precisely the same size and configuration as the size 2 Tiemco TMC8089 hook that I also use interchangeably for these types of flies. I like how the stinger-style of these hook models force the hook point further back and the hook bend lines up really well with a mono weed guard when you tie it in on the upper portion of the hook bend. In this case, I consciously chose the Gamakatsu hook over the Tiemco version for this particular fly because I wanted its black nickel finish for looks.
-- Mike