You are far enough north that you could put a few walleye in there to keep the perch under control, and they shouldn't reproduce. I'm not sure what a good number would be for your size pond.

So, bear with me, I am still learning...
Stock some minnows like fathead minnows to get a forage base for the rest of the fish (not sure what water temp should be), and a few smaller perch 3-4" so they will start on the leeches but too small to eat larger fatheads. In the spring, stock some more perch, the following fall, the walleye, 3-5".

I am guessing the WE would get rather large after a few years of keeping perch in check. So far this combo has been nice to swim with in our pond, you never see them. It is the large bluegill that is the nuisance in the pond, it thinks certain exposed body parts are good eating. Except of course my lures.