Hi Carl;
I'd strongly suggest boxing those lower control arms, and putting the bolts through a tube so you donât collapse the arms when you tighten them up. It won't take much to crack an arm in normal use.
Ask me how I know. .....
I just did the same install on the chassis going under my 70 Parisienne. It was a stock diameter sway bar, but same concept. On mine, and according to the assembly manual, the front bolts are only through the inside wall of the control arm, not all the way through like the rear bolt. I made my hollow spacers out of black pipe.
I wonder about boxing the rear control arms, as you need access to the nut that holds rear springs in place.