I may be a little late in the conversation - but we do a fair amount of walleye fishing here in South Dakota. Most of it is in lakes or in the reseviors of the Missouri River - in short too deep to really be efficient with fly gear. The walleye I've caught on the fly have been in some of the smaller rivers that are more easily reached with a sink tip or even a floating line with a longer leader. I don't know where you were originally intending to fish, but think smaller river. They can hold surprisingly large fish, especially during the spring spawn. As far as flies, Clousers are usually the way for me - baitfish pattern with weight to get it down and hookpoint up to avoid most snags on the bottom.

Tall