I fish those on a 3 way rig. Depending on the current, I use a 3/8 to 1/2 oz Walleye head jig with a swim shad, 3.5" a trimmed Thump Grub or a Scrub as my dropper and fish a bucktail fly on about 3-4 foot runner. I use a barrel swivel instead of a 3 way swivel as I don't get near as many malfunctions with a barrel swivel as I do with a 3 way swivel. I use 10 pound Nanofil for my main line and use 8 pound fluorocarbon line for the jig/fly rig. Sort of like a Dubuque rig I guess.
The only time I have caught walleyes on a top water bait was while skipping a catfish worm out of a logjam to avoid getting snagged. It's happened a few times where a walleye whacked that catfish worm as it skipped over the water in a few small open spots in the logjam. Talk about a surprise catch. A catfish worm all munged up with stink bait catching eyes. And some folks are all worried about human scent affecting whether a walleye will bite or not. LOL