A fence in front of the fence permissibility

90% of the respondents, however, are just monologuing here)

Unfortunately, you belong to that group with your wall of text ;)

Exactly not, that's why no one reads the sermon in the first post so carefully and often that they really understand it.
A simple sketch of the situation, for all I care with pencil and paper and then scanned, would really help to be able to help you properly.

Seriously? Can't you imagine the entrance/access on the left or right neighbors? With a simple pencil sketch, I suspect this would be the first 11 Ameisen post: why north and south are not marked there and paths, streets, angles to buildings cannot be recognized and so it can never be answered properly ...

People, let it be, I'm going to sift gravel ...

Do that ... Maybe it's better that way ;)

For a simple pencil sketch, I suspect, would be the first 11 ants Post: why north and south are not marked there

Apart from the fact that even hand sketches do not generally lack a northability, elephants do not consist of all ants ...

I am just imagining what that would look like, a turtle carrying 44 ants, there is no way a Discworld could fit on top of that...

Is that the question?

So to make a long story short:
could I put a double bar fence directly on the border next to his (neighbor A's) double bar fence and just thread my privacy screen there?

Why shouldn't that be possible if you keep to the maximum height?