How to create a complex stencil

[Jennifer]

Wow!  This took a gigantic leap in a totally different direction.

   . . .

But, the main point was the simple process that the doc stencil enables for editing in its in adulterer form.  Sorry if the explanation was confusing.

You have a lot more experience than I do with far more complicated drawings, so I'll defer to you. It just seems odd to me that Visio does not provide a way for to store a master shape in a custom shape file that is not part of any document and make it available to any document that needs it.