‘Three Bags Full’ is on Herbie Hancock’s first album “Takin’ Off”. The head features some interesting horn lines arranged for Freddie Hubbard and Dexter Gordon.
‘Three Bags Full’ is in D harmonic minor for the most part. Hancock emphasizes this by alternating between the minor/Major 7 chord on the first degree of the scale and the flatted 6th degree. In bar 18 he moves from Bb to Eb minor beginning a Temporary II-V Chain (Link). He pivots back to the top with an A diminished chord.
The 2 part harmony for the horns is all displaced by an octave (Example 1). Try to bring out these voices while playing the head.