I see where Craig Mathews of Blue Ribbon Flies in West Yellowstone, Mt. has now added Zelon to the deer hair wings. Instead of tying the zelon material at the base of the thorax for the shuck, the zelon is tied behind the wing just like the deer hair itself and then tied down back to form the trailing shuck.
It may provide some sparkle which may or may not be seen by the fish.
The top photo is a PMD and the bottom two photos are Sulphurs.