Mocking Up Firewall for Master Cylinder Studs

Just came back from Home Depot and bought a Grinder and hole saw that's just the next size up from the center register of my MC. Since my swiss cheese sheet metal only fits one way on my brake pedal assembly, I was thinking about using that and forming it so it hugs the firewall (I may be holding it upside down in the picture). Then mark the holes for the MC studs and connect the opposite holes to see where the lines cross. And technically, at that point, the MC should be located in that location, correct? Does my idea sound dumb?