i think coco mat or not, with 30-60 plants in 8 square feet the roots are going to be tangled. If you cut the mat into 4x4 squares, the roots will still eventually be bigger than that, and wrap around each other. If you try it, I wouldn't mind seeing how it works out for you, but I think in the end you will have the same limitations as if you didn't cut the mat. If you're looking for a perpetual harvest type flowering room, you could always experiment with it and try cutting roots away, but once you get that thing going it's going to be hard to get in there with all the density.

30 plants in 8 square fee is pushing it. I hope you have a strain that grows very short and even plants.

good luck.