When you cut the SS mesh, are the places where the wire intersects held together, or does the weave have a tendency to fall apart? I used some mesh in the past that just kind of fell apart when I tried to work with it and haven't used any since.
Scissor type metal shears. Try you're best to cut in the middle of the "row" you are cutting. If you bend a few of the short ends that stick out "up" and "down" to lock in the 4 perimeter stands, that can help keep your square from coming apart.