It’s hard to see, but the mouth of the fuel filler neck is fairly distorted. I made liberal use of the dead blow hammer to shape the flat disk to match the saddle curvature of the turtle deck skin so that there was a fairly good approximation of the surfaces. Holes for the nut plates were made using the wonderful 12” x 1/16 drill bit, then enlarged to #40 from the easy access side. (I had to drill from the back side to get accurate placement.)
Note that the majority of this page is already done since I purchased a pre-manufactured fuel tank. It’s kind of a shame that this is the only step worth documenting.
Fuel Filler Neck prep