Next step. Screw in new floor panel with the biggest sheet metal screws you can find.
Next beat the living shit out of the ridges of the new sheet metal to conform to the trans metal.
Then utilize your crappy welding skills to start welding the seams together.
Lots of grinding of the bad weld to do. Finally ended up getting some good ones tho.
After the seams are all welded up take out the sheet metal screws and weld the hole left behind joining the two panels in the process
Oh ya. Use this stuff where the metal is overlap. It prevents rust from appearing inside the seam.