Replacing metal under seat area

[Mgicm]

HI
So in my quest to rebuild this 51 AD, I need to replace the metal under the seats. I am not seeing a patch panel for this online anywhere except as part of the $500 entire floorpan replacement. Since I dont have access to a bead roller, has anyone done this and if so..how? Would a straight piece work across this span, could it not have the huge bead in it or would it need additional supports in that case? Sure appreciate the help.

thanks!