Ok, update. I rebuild the middle assembly again paying great attention to the bearing and tension. Made sure every bearing just made contact with conduit. It wasn’t easy while trying to then square up the center. Got square to about 1/8 over 5 feet. With a little more tinkering i should be able to get it a little better. Once reinstalled, I’m now getting circles that look like circles. On a build this size I could really see where stainless would other much more benefits to rigidity and smoothness over distance.
All in all, it is a great design and a great community that forum offers.