I am sending some info on the poison tung variant. I tied this fly for a number of guides in the Big Thompson- Rocky Mountain National Park area in 2009. It produced well for then and their clients.
The fly is tied with a very thin abdomen and large thorax (I coped this idea from Mike Mercer's micro mayfly and Charlie Craven's deep blue poison tung).
The bead is silver lined and over sized. I keep it in place with a thread base and super glue.
I usually fish this fly in a series and use a tungsten beaded fly for weight.

The fly can be tied with a tungsten bead replacing the root beer color but does not fish as well.
My guess on the effectiveness is the thin wine colored abdomen and the root beer bead. Nothing original in this fly just a bead and color change.
If you are not familiar with Mercer's or Craven' patterns take a look, they are great producers. freddyg

PS I would be interested in some info on your flies if time permits .