Stillwater, conventional, fly fishing wisdom is to present your chironomid/midge pattern in a vertical posture from the muck to the surface. I agree with this. There are always exceptions. I can recall moving from one part of a lake to another and trolling along a midge pupa, that had to be bobbing between vertical to horizontal as I rowed, and getting nailed. But, a stationary, vertical presentation toward the surface is predominantly called for.
That said, I have had excellent results with a horizontal presentation for midge emergers in the film. Retrieved back, twitched or wind drifting, a pattern tied and presented in a horizontal path does provide positive results on top.
Now I am talking stillwaters, re that maneuver. On the slower tailouts of rivers, a drag free, dry fly presentation is appropriate. A light wire hook is better on a river to maintain a mostly horizontal position for the fly. The rear end of the fly will cant downward because of the lack of a tail to prop the fly up in the surface, or pattern design.
With the Hi-Jinx pattern above, the fly is tied smaller on a size 16 hook. This is not a bad idea for some patterns: still go somewhat small for the hook size and then reduce further the pattern size on the shank of the hook. The positives of the pattern will overcome the perceived negatives of the exposed hook. Pattern + Presentation will usually overcome most negatives.