Kostov

When I got my buggy it has been bolted to the pan for likely 20 years with a pan gasket using bolts and fender washers. The body flange to attach to the pan was lifted on the inside between each of the bolts. It actually caused some stress cracking in the fiberglass. I did some grind and replace of fiberglass on the inside to get rid of cracking (while doing extensive fiberglass replacement to the sides where the roll bar whacked the body when the previous owner flipped it.) I have restored the strength but you can still see the ripple in the lip if you look inside my buggy. I just bolted the body directly to the floor pan without any gasket. It has been that way for the last 18 years without any problems. My buggy isn't some nicely sealed sedan anymore.

It sounds like you already have one of the solutions I was thinking about. I had considered using 1/4 inch aluminum strips on top of the body inside the car and then using countersink cap screws in that to bolt the body to the floor. Since my body lip was already all wavy I didn't do it, instead using regular bolts and fender washers again and painting them with the body. If you sink batteries into the floor pans the body will be supporting them (the body supports the floor on the Beetle pan) so your setup would be good. My fiberglass body has had no problem supporting 3 Optima batteries (125 lb.) on each side for the last 10 years with the bolts and fender washers.

I also left out the very front and rear bolt that attaches the body to the floor. It is fairly common to have the floor boards crack inward from each corner because the pan horns don't flex but the sheet metal floor is flexes along with the fiberglass body. That fight gets taken out on the corners. I had to do crack repairs to all 4 corners when I got the buggy but have only had to repair one corner a second time, the right rear where the SLI battery used to sit. That whole area is a collection of rust and crack repairs.