scales for guitar - Another way to think about "harmonic minor"

Most of the cases in which you would deploy a "harmonic minor" sound are in the ii -V part of the minor cadence. Once you reach the target minor chord you are free from a specific mode constraint.  The scale tonic is actually rather insignificant until the one-minor chord has been reached.

Here's a scale exercise that reflects this aural reality. You'll notice two different ways of altering a major scale to sound the relative minor.