some problems with mensural music

[Denis . Roegel]

Hi,

I am trying to typeset some 16th century hymns with lilypond.
I mostly can make it work, but I have a few remaining problems.

My working file is:

  http://www.loria.fr/~roegel/tmp/questions.ly

My problems are the following:

  1) I would like to show the tempo with mensural notes, not as it
     comes out in the above example

  2) the ligrature \[g1( f)\] comes out with a slur, but I would like
     to avoid the slur; however, if I remove (...), the synchronization
     of the lyrics is screwed up ; how can I put one syllable on
     \[g1( f)\] without having the slur appear? In my 16th century example
     which I try to mimic, there are no slurs;
     the same problem occurs with other constructions such as \[d\breve( c)\]

  3) I would like a key like mensural-f, but on the third line, not on the
     second line from the top; is this possible?

  4) for more recent layouts, is it possible to change the slope of
     the beams?

Thank you very much in advance!

Denis Roegel