With the water cold now like it is I would slow way down pulling cranks. Last weekend I was pulling at 1.2-1.4 mph and did pretty well.
I was on Mille Lacs on Saturday pulling #7 Flicker Shads along the north end break in the sand during the day. Walleyes were smashing them at 1.8-2.2MPH. While everyone was in shallow jigging the crank bite slightly deeper seemed to be very good.
In Shallow water like the OP mentioned. I have pulled spinners behind planer boards in the depth mentioned and even shallower…. like 2-3ft of water. Put a larger sinker up a few feet to get the spinner down in the water and it can be a good tactic.
I always run boards in shallow water as it seems those fish seemed to sometimes get spooked by the boat and push away. Especially in clear water.
Also you may want to look into a #1 offshore tadpole. These things are awesome when pulling spinners. 10 feet back at 1.25 MPH is 6 feet down, 18ft back is 10 ft. They’re good for deep water as well. 123ft back 1.25mph is 34 feet down. So they’re very versatile.