Excellent report, Bobby P.
Funny...on Lake Erie the saying is, "Speed kills!" in walleye trolling. Last weekend I caught several eyes pulling cranks on leadcore. I'm in the habit of trolling at 2 mph, more or less, because at that speed I always know where my lure is running. (Leadcore is very speed dependent--it rises when you go faster, sinks when you go slower.) Once that day, when I found myself in shallower water, I sped up to 3.5 mph to bring the cranks up and over the bottom. Coming off that hump, a walleye slammed the crank, before I slowed down.
I tried speeding up and moving shallower a time or two the next day, when fishing was tougher, but nothing happened. Still, it's worth experimenting with, rather than sitting in a rut. Thanks for passing it along.