Turn over definitely affects walleye – as do most changing conditions. As with all changing conditions, expect a period of tough fishing until the walleyes (and you) adjust to their new patterns. As the name implies, turn over is the warm surface water cooling to a point where it gets colder than the bottom water. The colder top water sinks and the warmer bottom water rises. This “mixes” the entire water column – often to the same temperature, effectively eliminating any thermoclines.
I have found the after turn over, the best areas to look for walleyes are sharp breaks close to deep water. Often these are fairly small areas so using a slower technique like rigging or vertical jigging are often best. You should be able to use your depth finder to find where on the break the fish are holding – or better yet an under water camera. Then present your offering at that depth or slightly shallower (walleyes often sit below the bait fish and feed in an upward direction).
One big thing we do in the fall is switch to larger minnows. Our best by far is to get creek chubs. They are very hardy, live a long time, and when a walleye is close – chubs go crazy. This aggressive response is probably what triggers walleyes more than anything.