I find around 3 inches to be a great sculpin size in many of my favorite Southern Rockies Rivers. I achieve that preferred size by tying a single hook pattern with a slightly longer than the standard “1 hook shank length” tail.
This also adds to the erratic movement, but what truly adds the movement is the combination of oversized lead eyes with a “slider” style deer hair head. Add some slightly oversized hackle and rubber legs and it’s the perfect combo, in my opinion.
The slider bugger is my go-to sculpin pattern when I’m needing something larger than my Cousin It Sculpin Jig pattern. It's easy to cast, gets down quick, and has great action when dead drift or retrieved."
The Fly Shop of the Great Lakes