When I built mine, my mentor recommended doubling up that bulkhead, with a flat piece of .063 sandwiched in between. Reforming the flanges of what was to become the forward one of the pair was a bit of work but doable. Recommend shimming instead of totally reforming as that reduces work-hardening of the bends.
Perhaps that will also require relocating the holes in the tailspring fitting, I don't know.
This is a known problem, unfortunately, that has bitten other RV-3 owners. Good luck with your repair!
Dave