Here's a FOTW, which is a version of the best BWO pattern I've fished.
http://www.flyanglersonline.com/flyt...041309fotw.php
I really like it with the loop wing as shown, but as a practical matter, using an antron wing / post makes for an easier tie and a more durable fly.
This fly produced for me better than any other BWO I've tried on a great little tail water fishery in the Central Mountains of Idaho - a river I thought of more as a nymph and midge larva stream until I started using this pattern there.
John
The fish are always right.