BrentS: you have a valid point and I did take that into consideration. I would make several neck posts that would cover the range of ball socket (except stormtroopers and clone troopers, to big of a ball). From what I have seen in most new figures as they are taken apart at RS photo gallery, the balls are close, not perfect. If the head is loose on the neck pole, then all you have to do is fill it with some plastic welder 2 part epoxies that you can get at Wal-mart and cover the neck post in either Vaseline or saran wrap and sick it in and let the plastic cure on the neck post. Otherwise, I will make various neck kits that will be made to order. Example " I would like a Hoth Leia neck with a small female ball joint, please." Once I have an inventory of stock necks, I will be able to adjust to the needs of the customizer. Of course, some of the fun in customizing is solving problems that come about doing chop shop toy designs. Bottom line, I have proven my plan could work and that is what I was trying to accomplish and now have succeeded. As for distribution, for right now, I think I will work on a case-by-case scenario based on the needs of each customizer choice of body they are customizing.
Thanks for the input and I deeply respect your feedback, it does shed light on to other issues besides the engineering design process.