I am proceeding to work on my font, also thanks to the competent help of this forum.
Now, I think I have set metric values if they are not perfect, at least such as to produce an acceptable result.
However, one thing does not work: subscript letters (not figures).
At first I didn't set any value in OtherBlues, then I tried, but the result is always the same on Windows (with Adobe Acrobat Reader at the default resolution):
We see that <v> <w> <x> <y> <z> are not aligned at all. I also tried to modify the values of the StemSnap, again without result.