If you are in a pinch, we use a combination of Muenster. Monterey Jack/ Mozzarella (never pre shredded). This seems to be a pretty close approximation. I've also read that Butterkase is pretty close as well. I have made it with Wisconsin Brick Cheese before (I've found it at Churchill's Briarfield sporadically), and i can tell you, this is not the most crucial piece. If you get the sauce and pan/ dough down, any of the above options are great. I've heard that very few actual Detroit style pizza places even use the brick cheese. I'll definitely check out Sofo's. good luck!

Also, Amazon has it https://www.amazon.com/Brick-Wisconsin-Cheese-Mild-oz/dp/B00HYMXJO6