A little more progress to report. Monday he'll probably get the pieces that I made up welded in place. Right now, his biggest concern is finding the correct shade of seam sealer and "E-coat" that was put on at the factory.
These pictures show the flat plate that was welded inside to the bottom of the xmbr. The vertical membrane will be welded to this plate and the cap (via plugwelds).
1957 Austin-Healey 100/6 Wine Red
1961 McCulloch R1 go-kart Screaming Yellow
1995///M3 Coupe Dakar Yellow Eurosport Twinscrew S/C
1999///M Rdstr Cosmos Black Eurosport Twinscrew S/C
1999///M Coupe Estoril Blue Eurosport Twinscrew S/C
2001///M Rdstr Steel Gray
2011 X5 35i Sport Deep Sea Blue/Cinnamon