I have a number which begins with two baritone vocal solos (different characters in a musical theater score). The orchestration is light. For the first verse, 6 pizz violins play an ostinato figure, in unison, an octave above the first singer. For the second verse, a single woodwind takes over the violin part and soft accompanying piano chords are added below. A string bass plays the bass line (pizz) under both verses.
I am seeking advice on which reed instrument to use in the second verse. My available instruments are a clarinet or a flute. The problem is that the range is roughly from Middle C to an octave above. If I use the clarinet, the player would often have to play throat tones and repeatedly transition over the break. If I use the flute, it would be primarily in its lowest (and presumably weakest) octave.
I am primarily concerned with tone quality I might expect in a live performance (assuming professional caliber musicians). I want to minimize the possibility of intonation problems or variation. I am concerned about the smoothness of the transitions over the break if the clarinet is used. I wonder if the bottom octave of the flute will "speak" clearly enough, or get a bit muddy. I am not worried about the volume because there is very little else going on and the vocalist will have prominence anyway. It is also likely that the singers and pit will be amplified.