Tweaking mandoline tabulatur

[Helge Kruse]

Hello,

I write for mandoline with LaTeX and lilypond-book. The book includes a lot 
of small pieces included in this way:

\begin{lilypond}
mel = \relative c' {
 e\upbow f\downbow g a b c d e f g a g fis e d c b a g f e d c b
}
\header { title = \markup { "Hänschen Klein"  } }
\score { <<
 \context Staff \mel
 \context TabStaff << \set TabStaff.stringTunings = #mandolin-tuning 
\stemDown \mel >>
>> }
\end{lilypond}

This gives a tabulatur, but I would like to tweak the result a bit.

1) How can I shrink the length of th stems in the tabulatur?

2) I would like to add some up- and down arrows above the tabulatur. When I 
append \upbow and \downbow in the meldoy "mel" I get them both in the notes 
as well as in the tabulatur. How can I set this only abot the tabulatur? How 
can I define other (smaller) arrows instead of the guitar

3) The stemDown is obviously ignored. There is no further hint in section 
7.5.2. of the Lilypond manual. What my be wrong?

4) The Umlaut ä does not appear in the output. But I get a lot of 
assertions:
Pango-CRITICAL **: pango_coverage_get: assertion `index >= 0' failed
How can I use Umlaut?

5) Is there a way to set the stringTunings property globally, so that I dont 
have to set it in each pieces

6) How can I write notes without staves? The following excerpt shows the 
idea, but I need only the notes, no pitch, no key, no staves.

Statt
\begin[fragment,notime,staffsize=10]{lilypond}  { c''8 c'' }
\end{lilypond}
dann fast
\begin[fragment,notime,staffsize=10]{lilypond} { c''8. c''16 }
\end{lilypond}.


Hmm,  these are a lot f questions at once. I have tried to solve them by my 
selve, but get stuck. Honestly, I gathered the problems and put them in one 
or two small samples. I hope you can help me.

Best regards,
Helge