OK I got some sleep but it wasn’t easy with the problem of not enough gas in the car to get from El Paso to Phoenix before tanks dry, not to mention getting from Dallas to El Paso.
The problem was I made my constraints too constraining, the biggest constraint was not allowing the top of the tank to be higher than the bottom of the dash molded into the bucket body, which after I thought about it was more than silly since the frame rails are going to be taller than that. So I went back and recalculated after moving the top of the tank to the underside of the top body flange between the dash and the rear body kickup. This got me to 28.75 gallons which might get me to Phoenix from El Paso, but probably not to the E85 station in El Paso from home. So I laid the rear face of the tank back until it just touched the inside of the body at the upper outside corner. This gave me about 31.33 gallons of capacity, which got me to the E85 station in El Paso with a tiny margin of safety for headwinds.
Now the fun part is going to be getting gas in the tanks without getting gas in the cockpit with me. I think there is room to mount a gas filler on the back of the bucket above the top of the tank, but I don’t know if there’s enough room for the hose from the filler to the tank. That is something I’m going to have to find out and fix when I’m doing mockup of the tanks in the body, because working on that after paint and powdercoat is too late. But it is something I can fix, have to fix, if I want to drive my car.