I've gotten away from hackle unless it is palmered on a high riding elk hair.
My box has either comparaduns or CDC tied on pupal hooks with a poly trailing shuck with some pearl angel hair mixed in with the poly.
I primarily fish the lackawanna, and history has taught me that the biggest surface feeding browns on that river, 16"-20", sit on the micro currents in the real smooth glassy water, often on the edge of a shelf of embedded rocks. So the cast often has to land exactly on the seem or it gets sucked into the eddy water.
It may seem tangental to this topic, however I have witnessed these fish sitting less than 6" under this glass water, comitting to the surface, before the natural ever gets into its window. I know the bug is outside its window cause the fish will have its beak out of the water, disturbing the film well before the fly can enter that area where the whole fly can be viewed from that vantage point.{this is why I cast downstream, so I can peg the micro currents with out disturbing the film}
Now, if I undeniably see the trout take a high riding dun, feeding in this manner, I use a comparadun in the proper body color for the season, and always with a trailing shuck as explained earlier. I like the comparadun cause it is heavier and depresses the film more than standard hackle. Unless I see the bug above the surface, I go with CDC tied straight out from the eye of the hook, over a dubbed body, with the trailing shuck pointing straight down, all on a caddis bend hook. When the fly is on the surface, the only thing the fish can possibly see is a bit of the body, and the glowing shuck due to the angel hair strands, and the distortion the CDC creates pressing on the film.
The fish in my avatar was taken on a size #18 BWO tied in the manner explained, over a fish feeding in exactly that type of water.
I will sometimes use CDC to post a parachute, but that is usually just cause I wish to play at the vice.
Just my $.02