[tablatures] Positioning of text elements

[Frank Stefani <frank.stefani@xxxxxx>]

Hello all,

I open up this new thread as the string naming question
could be solved due to hints of Carl Sorensen.

Next questions:

1: How can I move the "instrumentName" markup
   from the example score below closer to the TAB?

2: I want all string names appear centered within
   their box. How do I achieve this?

General question:

3: Is it possible to position (non-note) elements freely
   with Lilypond? It would be nice to place or anchor
   custom text (or GROBs) anywhere.

Regards,
Frank

---<snip>---
\version "2.12.2"

% Koyabu left hand tuning: C G d a e h
#(define-public koyabuLH  '(35 28 21 14 7 0))

global= { \time 4/4 }

myNotes = { g16 e' c' b c e, c' e, g, e' c' b c e, c' e, }

<<

  \new TabStaff \with {
    instrumentName = \markup \magnify #0.6 \override #'(baseline-skip . 1) \column {
      \box \pad-to-box #'(0 . 1) #'(0 . 1) C
      \box \pad-to-box #'(0 . 1) #'(0 . 1) G
      \box \pad-to-box #'(0 . 1) #'(0 . 1) d
      \box \pad-to-box #'(0 . 1) #'(0 . 1) a
      \box \pad-to-box #'(0 . 1) #'(0 . 1) e
      \box \pad-to-box #'(0 . 1) #'(0 . 1) h
    }
  } {
    % koyabu left hand
    \global
    \set TabStaff.stringOneTopmost = ##f
    \set TabStaff.stringTunings =  #koyabuLH
    \set TabStaff.minimumFret = #5
    \stemUp
    \relative c''' { \myNotes}
  }
  \new Staff {
    % cello
    \global
    \clef bass
    \key g \major
    \relative c { \myNotes }
  }

>>
---<snip>---