Here is a quickly done SBS. Not really set-up for SBS.
I make a yarn loop (your choice color, size) and fill with ball of UVepoxy. Cure, add some color with marker pen (your choice color) and finish the fly.
These flies work well. One of my go-tos for Rainbows, Dollies in Alaska.
I tie them both ways. I have always wondered if it really matters. These are small flies - size 6, 4 - we fish them on the bottom with short twitches. They get tossed around. Its not like they are getting stripped like a clouser. I think they often get taken as a single egg by foraging Rainbows. The Dollies like 'em a lot..
One of these days, I'll fill up the bathtub and see what they look like.