Hi,
I tried to go deeper in my problem, trying to understand where it
starts to do not work, and it seems that as soon as I \remove the
"Timing_translator" from the Score context, I lose the possibility to
break lines. On the other side, I cannot have it in the Score context,
and only remove the Default_bar_line_engraver (and consists it only in
the Staff context)
A kind of solution is to use tuplets and cancel the bracket and
number, and put manually the barlines but this would make impossible
to use tuplets inside each single rhythm (in this solution, a tuplet
would be in fact a nested tuplet, and if I hide them, I cannot see
them!). Also the syntax start to be really obscure.