I did something similar, I used the short panel piece , and fitted it to the bottom of the new floor board. And then I put up the new inner panel up, and where they overlapped, I marked it (longer that needed),and trimmed the two to fit, and finally welded them together to make one whole section. It took little time, but the fit was great, and used auto seam sealer to fill in the gaps. (kinda proud of myself, I figured out how to upload pics. Yay !!!). Be safe all , Mike
