Would it not be fairly easy to create a variation of
\RemoveEmptyStaffContext so that lines consisting only of rests would be
reduced at least to one line of multimeasure rests so the flute, etc.
player can count their rests? It is typical of French instrumental
parts to put each pair of instruments on a score which has two staves
when the parts are different and one staff when the two instruments play
the same thing ( a2 ). This is common in orchestral music of Ravel,
Debussy, etc. and it works fine to use \RemoveEmptyStaffContext except
when both instruments have rests that happen to occupy a whole line.
TIA for considering this,
Paul Scott