I used 4-40 to bolt them in the belcrack. No problems to report there. They are now in REvolutions. I have a little slop in the controls but it is not hurting the performance at all. As for thread engagement from a tool maker perspective thread strength is max with only 3 threads engaged. Anything after that is of little bonus.
Put the right hand thread with jam nut in an accessible place to be able to adjust. The housing is made of aluminum so you can use a harder material for the rod but since the housing has the weakest material anything harder and heavier than that goes on for the ride.
As for jam nut I don’t use one. I painted thread locker on the screws threads and let it dry. It acts li a screw with locking patch on. After I was happy with alignment i put another drop of locking at the base of the screw. Keep in mind my application is electric and I would definitely use a jam nut for IC.

Spoke with Tom Morris a few days ago about getting some ball links.  It seems that he has depleted his stash of the Rocket City #87's.  He recommends, and is now selling, the DuBro 3mm ball links; I went ahead and ordered some for my use.

Best regards,

Brew