The griffiths gnat is usually the ticket on midge hatches on the current from my experience. That being said I carry a few midge soft hackles, like a Syl's midge I believe. Honestly though, I usually use this in Arkansas on the tailwaters more then the current. I agree with Gavin though, if they are eating dries it is usually Caddis at the current, rarely do I see them sipping midge dries exclusively. The exception to this also is the tricos in the summer.