I wonder, also, if there is a connection with the shape of the human hand. I'm a (perpetually) intermediate piano student, and my teacher decided it was high time that I tackled scales (arpeggios, 4-note chords, and whatnots) in the different keys. I've been struggling with B flat major for some time, because the cross-overs in the R & L hands are different, and the scale doesn't start with fingers 1-5. The piano seems to have been designed with the human hand in mind, and my teacher explained how the cross-overs (fingers 3 and 4) relate to the shape of the hand. in relation to the layout of octaves on the keyboard.
Alongside the cosmic correspondences of music theory, the whole piano design, to me, seems to be based on the capabilities and limits of the hand.
Astrologically the hands are ruled by Mercury. Who gets short shrift in modern astrology, IMO; because anciently this planet was Hermes, from whom we get Hermeticism. Mythological Mercury/Hermes, was the one god who could traverse the celestial realm of Mount Olympus, the earth's surface, and the underworld. Another underworld connection with music being Orpheus.
I think a Mercury -Venus conjunction would be helpful for musicians.
Then some forms of music don't use the typical western octave.