Update: Finished drilling the big holes in the top to allow the jack points to dip into them, then fit them up with thick walled tubing to surround and capture the jack points and measured for square. I got them to within about a 16th of an inch and marked with tape to locate the tubing, then tacked and checked again.
Finding them still good I welded them around, and put beads on the cuts I'd made earlier to conform the part to the bend of the car's underside.
Trying to decide now whether to ties these brackets together with a piece of big (but thinner) rectangular box tubing to prevent lateral stress on the jack points. It would seem overkill and make it very much harder to install these parts in the field, but still I ponder.
The next step is getting a squared box on the ends of these, with the through holes level and square to each other on the same plane, since on installation these bars each tilted in slightly (see top pic), making use of the existing holes problematic.
I'll probably get after that tomorrow or Sunday.
