Try trolling or casting a single hook rooster tail with a worm / crawler on it.
Fish at entrances to small coves and bays but stay in at least 20' of water. Once you catch one, stay in that area as white perch are almost always in large schools. Braun bay and 19 mile bay have all,been good producing areas of white perch.
There are some real nice white perch in Winni and I consider them to be the best eating fish in the lake!
Good Luck!
Dan