I went to check out the passenger side, pulled the mat, and -- to my horror -- discovered not just small holes s but major elements rusting away. Egads!

That is totally open almost all the way across!
I was going to fiberglass it, but then remembered Wolf Steel in Quebec. US$80 and I have a new floorpan. Is this the best approach? Should I do something else?
With thanks and cheers,
phaetn