I was concerned that the slop you noticed indicated a problem with your particular balance bar kit. I went out and checked my own this morning. There is virtually no play at all between the spherical bearing and the balance bar tube in my kit. The bearing slides nicely from side to side, but you can't feel any play if you try to move the bearing in the tube using the threaded rod. Here is a photo of mine:
Attachment:
DSC03923.JPG
I had to take it apart to model it in 3D. The spherical bearing in my kit is very well secured on the rod by 2 nuts. one on each side. Is there any chance your bearing is loose on the threaded rod? I can see where that might make it feel sloppy.
Also, I notice mine is very different from the kit they featured on their website, at least the photo of it. It looks like this:
Attachment:
Wilwood-Balance-Bar-Sm.jpg
Looking at the two of them, and mine in the flesh, it looks like the materials and machining on mine is quite different, and much improved, over their photo example. Which does your look like?
Cheers,