The floor has been replaced from front to rear. The flat section on the rear was a piece of 16 ga hot rolled that the owner had, and hindsight being the great educator, should have been the last thing we used. I'd do a piece of cold rolled 18 ga with bead details, and wouldn't have all this to contend with. BTW, floor has been installed for some time now, Kyle just uncovered it...
Thanks for the comments, Bomp, glad to hear some of the posts here have helped out!