Thanks, AndyF.

I'll keep that in mind (that you have one sitting in the attic) as a last resort.

I was thinking I could make a thick rectangular plate that will fit behind the two vertical bolts on the right side. There appears to be enuf room for that. Then tack weld nuts to the plate.

The single bolt on the left side might need some additional thought. Perhaps tack welding the bolt near the bottom?