I think you might be confused as to what I am doing...

I need to use dynamics for a couple of reasons.

1) The Newtons Cradle is an experiment that shows how energy is transfered from one object to another
2) I need passive and rigid bodies to allow the dynamic transfer of enery from one object to another and foor those objects to be effected by forces like gravity
3) The transulcent wires that hold the ball bearings in place need to show mass and weight whilst they animate, this in turn would make the transulcent wires appear stiffer than they are

The best solution to make sure all these are adhered to is to use dymanics, I do not disagree with the approach you have suggested, I just do not believe that it is the right approach to take for this small project.

Here is an initial test on a single ball bearing...
Newtons Cradle Dynamics Testing and Solutioning - YouTube

At the time of posting the video was being post-processed by you tube