Just as an experiment, here are a few chord progressions given as shepard tones. I was curious to see/hear how they would affect the perception of voice leading. (The intonation is just: powers of 3, sequential.)
C Major: ii-V-I
C minor ii-V-i:
A harmonic minor ii-V-i:
It begins to introduce questions of voice leading and of register… and orchestration. That will all come later.
In any case, perhaps it is a useful spreading of the powers of three back into the powers of two, for the ears.