Napoleon - Welcome back to film

I use development similar to what you describe when I have an image with very high contrast. The initial development brings some density to the shadow regions, but when you leave it without agitation for a long time, the developer gets exhausted locally near where the highlights are, so you do not get as much density there as you would with constant agitation. This can be taken a step further by doing the stand development in the cold - such as the refrigerator.

That said, I don't like the idea of doing something where you have too many unknowns - if you are dealing with old film and don't know how it will respond, I would use a developing technique which you know well, and when experimenting with a new developing technique, use a film which is a known quantity - that way you will be able to understand what is doing what in your process.