1. How can I do the shape test for glass bead incoming inspection? I look up to AMS2431-6
3.10.7 Shape
A visual count shall be made of three fields of approximately 100 beads each, on the sample prepared as in 4.1.6 using a microscope with 20X magnification and sub-stage lighting, or an optical projector. The three results shall be averaged and compared to Table 1.

I think this method is difficult to perform, since how do I know each field contains 100 beads? Can you advise me other way to do shape incoming test. By now, every time we buy a new lot glass bead, we will do incoming test , including shape and size

2. In SAE J443,there are two type of saturation curves, however I can’t understand this type of curves,

My question is when can this saturation curves can be used ? In SAE J443, it states that this will occur only when process variables do not permit attaining earlier data points. I don't understand this means. Can you give me detail explanation about that?