The plates were made to have something for the bar going across to mount to instead of just welding to the existing tower. It's a lot thicker going from 18 gauge steel to 1/8 in (.120) steel.

I plan on welding a bolt on one side, inside of the tube with an adjusting nut to tighten up the assembly to give it a good pre-load. Though I like your idea of putting heim joint there. Might not be a heim joint, but it'll be something of the sorts. I'm really good at fabrication, but I'm also very cheap. Heh. But I'll check into them at the hardware store. I'll see what I can cook up.

The plate itself will be bolted down via the shock mounting bracket bolts. They're large enough and a grade 8 to be able to hold it in place. The initial shape was made by using cardboard. Once I had the shape of it, I rough cut the flat steel and then shaped it to fit into the nook on top of the tower. The outer holes were drilled out using a step bit. They're a lot larger than the bolts, but I wanted enough wiggle room to be able to remove the bar if I needed to. The center hole was also drilled out with the step drill, multiple times to remove as much material I could. I basically just used the shock upper washer as a template, and scribed around it to get the general shape and size. I finished the hole and cleaned it up using a dremel and some cut-off wheels. I'm pretty good with a hand grinder from back in the days when I was a trim die machinist at the forging plant.

Hopefully I'll have it done today at at least to the point of getting it painted up to look all pretty. Then I have to figure out how to cut the trunk carpet trim neat enough to make it fit.