I turned the rods all the way through the inside nuts. the insides of the tubes were machined out to fit perfectly over the threads, so that they would line yp properly. I then welded the nuts onto the tubes. There are left and righthand nuts on each tube, so that you have proper adjustment to preload the diff if you turn the tube to either side, it's then locked into place with the extra set of nuts.

Here they are set at about 500mm from the center of the holes in each mount on the ends. This is just about the length they will be adjusted to when fitted. Like this there is still a good 50mm of thread inside each side of the tube, so there is plenty of space for adjustment in or out.

I'm really starting to itch to see how this will work.