view from the rear.

there are 2 layers of 1/8" thick steel instead of the crossmenber.
i took a 1/8" steel pipe about 8" in diameter and about 6" long.
cut the pipe open at the weld and then forced it open until it was the right contour of the floor.
then heated the pipe and bent to match the reverse curve of the floor.
after it cooled down i cut the pipe into 2 pieces so the curves matched each other.
welded one strip directly to the floor and the top of the crossmember.
drilled several holes in the other strip and plug welded and continuous welded it on both sides of the lower strip to the upper strip.
then welded the lower part of the strip to the bottom of the crossmember.