Break the quartet into two duets (Soprano+Tenor and Alto+Bass). Have each duet sing their line alone against a metronome at 60 BPM. Then bring the four together. This exposes the "better" arrangement's independent lines, ensuring no one is hiding inside the chords.
[Violin 1 & 2] E - G - B - E G - B - D - G spartito la voce del silenzio quartet better
The piece could unfold in three main sections, each representing a different aspect of silence and its voice. Break the quartet into two duets (Soprano+Tenor and