I have a 94 with the same issue.  For an interim fix, I cut out the floor and from the inside reassembled using sheet metal.  This year, I plan to remove that and fab a better bitting box that I can use for some under seat storage.  The biggest issue that I encountered was reattaching the seat mounts for the backseats.  Fabricating you’re own will require more careful planning to ensure you can bolt your seat backs correctly.  Good luck!!