[Richard]

I think I would try and stay away from the middle of the car. I picked up an old (large) bumper jack and use it on the quick jacks. You can also use any of the lower suspension pickup points and transaxle cross member. I’ve included a picture of the interior of the sponson where the gas tanks live. The outside of that area is covered by fiberglass and I don’t think the floor would work well either IMHO.

If anyone is interested I have pictures of the gas tanks and filler necks. The filler necks have flapper valves in them for surge control.