I've done the same thing for others, shaft collars with a bolt welded on each. I pick bolts that thread into the vehicle's lug nuts and use cone seat lug nuts to hold the bar in place. That way the lug nut tool is also the jack access tool.
On the shaft collars from McMaster, note that there are two steel versions, one labeled "weldable" and the other isn't. Those that aren't appear to be made from 12L14. They're steel, you can weld to them, but that "L" means that there is Lead in the steel alloy and welds won't stay stuck long term.