Tweaking diagram

[Gerardo Ballabio]

Hello all,
source file and compiled output attached. Please forgive me if this
isn't a "tiny example", but I believe I need to show the full thing in
order to communicate clearly what I am trying to do.

I'm creating an illustrative diagram to demonstrate visually the
relation between the different clefs. I've managed to get quite close
to what I want, but there are a few issues that I haven't been able to
fix:

1. In the upper double staff, I'd like to draw the staves closer to
each other. Specifically, the vertical distance because the central C
and the preceding B should be the same as for all the other pairs of
notes. I tried to set StaffGrouper.staff-staff-spacing.basic-distance
to a negative value, but apparently that is not allowed ("programming
error: insane spring distance requested, ignoring it").

2. In the lower staff, in the first and last measure the note stems
are too long. This is because they aim towards the "central" line of
the staff which is actually outside it. I haven't found a way to tweak
the stem length, nor to shift the staff up or down in another way than
by changing Staff.StaffSymbol.line-positions.

3. Also in the lower staff, I'd like bar lines to extend from the
bottom line of the preceding measure to the top line of the following
measure, that is, they shouldn't leave the lowermost space "open".

4. Is there a way to center horizontally the note names on the
corresponding notes, instead of left-aligning them? I believe that
would look better, especially the spacing between "fa" "sol" and "la"
looks awkward.

Thanks in advance for any help that you'll be willing to offer.

Gerardo

note.ly
Description: Text Data

note.pdf
Description: Adobe PDF document