If and I do this several times a year, I was going to fish for smallies on any river in Michigan, the first fly I would tie on would be a chicago leech. I say this because I've caught literally hundreds of smallies in michigan rivers on this pattern. I've caught smallies ino other patterns too, but for me this is the go-to fly for that situation.

recipe
3906 #6 or #8
black 6-0 thread
gold 1/8" bead
black marabou tail
body of black leech yarn
after you tie in the tail and wrap the thread up to the bead and finnish the fly, Use a brush
(mine is made of a popsicle stick with a piece of the hook part of velcro 1 1/2" long glued to one side) to brush the leech yarn up and back to form sort of a horse mane look.

alternatives that the smallies really really like....

on the tail add about 6-8 strands of chratruese Krystal flash to the balck marabou
for the body use Black peacock Ice Dub instead of leech yarn. Brush out in the same wanner though.

This fly kills them below the dam at Mottville