Rehearsal marks, percent repeat

[Antonio PALAMA']

Moving from 1.2.17 to 1.4.12 some of my favourite commands
do not work as expected

The command I had standardized for boxed rehearsal marks, i.e.

\mark 
"{\\font\\twelverm=cmbx12\\twelverm{\\hspace{10mm}\\raisebox{0mm}{\\fbox{1}}}}"

makes some additional white space to be inserted before and after the barline
preceding the \mark command.

The command I had standardized for "circled" rehearsal marks, i.e.

\mark "{\\font\\twelverm=cmbx12\\twelverm{%
\\hspace{0mm}%
\\raisebox{-1mm}{%
\\setlength{\\unitlength}{1mm}%
\\begin{picture}(7,7)%
\\put(3.5,3.5){\\circle{7.0}\\makebox(0,0){1}}%
\\end{picture}%
}%
}}"

is not usable at all (lots of white space before and after the barline).

Do you have any suggestion to solve the problem?

I would like to look in the sources to see if I can do something
to solve the problems outlined in my previous posting about
percent repeat:

- Too wide percent repeat measures
- It is not possible to have multiple precent repeat behave a la "skipBars"

Where should I start looking?
Is there a place in the documentation or in the sources where the
algorithm used for horizontal spacing is clearly described?


Thanks a lot for your help,

Antonio Palama'