I spent most of the afternoon backtracking and making a new set of ring mounts for the control stick assembly. I welded them up, which distorts the big ring quite a bit despite my best efforts to control the heat.
After cleaning out the scale on the back side of the welds, I did the best I could to make the mount ring round again by squeezing gently in the vise and followed up with the air spiral sander and valve lapping compound. After a nice, smooth fit I marked and drilled/reamed the bolt holes to the final size and the bolts fit perfect and sit flat, just like they should. These turned out MUCH nice than the previous iteration. I bead-blasted the mounts and once the oil holes in the top I’m ready to weld the control stick pivot brackets to the main tube. That will hopefully be done tomorrow.