Fall (Late Sept-early Nov) is about the only time I target them-its just too hit or miss other times of the year. I do catch quite a few incidentially when I'm fishing for bass. I catch them on spinnerbaits or jerks but I've had them hit tubes and even hula grubs. In the fall I'll fish for them at first light until about 9 AM, then switch over to bass.
In the early spring the area around mid-island is a well known wiper hangout, especially the water on the north side of the island and the mouth of Denver cove. Guys go after them with just about everything-spinnerbaits, cranks, kastmasters, rattletraps. I think the trick is to cover a lot of water. I don't troll but this is a good way to get your lure in front of a lot of wipers. Once the warmer weather comes, they tend to move down to the lower end of the lake and hang out around North and South marina coves. Trick is to be out there at first light-they head real deep once the sun is on the water and its hard to locate them. Look for the birds. Ed