Well I absolutely DON'T have a handle on it. Most of the time I feel like I'm barely hanging on. What it really comes down to is that all notes work all the time if you're "convicted" about it and you approach it and follow it nicely. The different theoretical 'methods' are just various systems of organization. I find that different 'systems' work better in different situations.
For example; the moving in m3rd's stuff works great over a "series" of ii-V's or ii-V-I's, but it's not necessarily great over a stand m7b5 chord in the middle of a tune. And of course it's all player and groove dependent. That's why music is so cool - no endgame.

The melodic minor thing seems to be well covered, so responding here to a tangent...

When I started dinking around with what I thought Scofield was doing over static dominant chords, I kept stumbling onto the 'm7b5 up a 6th from the root' thing. In relation to the root note, the intervals of a m7b5 arp up a 6th are: 6,1,b3,5. I call this the Scofield "sweet n' sour" sound (maj 6 is sweet, b3 is sour), that is, over a straight up dominant chord.

I really liked the way the m7b5 arps fell under my fingers, so I started screwing with them some more. It only makes sense that you could also play m75b up a 3rd from the root of a dominant chord, as the chord shapes immediately suggest such... for instance, G#m7b5 = E9/G#. Over the root, a m7b5 arp up a major third yields the intervals 3,5,b7,9.

From there, I started tossing in diminished, augmented, wholetone, and melodic minor stuff with the m7b5 arps. I have to admit that I've never really thought about it much past that point unless I was in an academic environment, such as teaching. For the most part, it's been some combination of following the ear and letting the fingers do the walking. I understand the differences between augmented and diminished, and between major and minor thirds, but I'd never allow good taste or proper academics to get in the way of making a choice, to a fault.

... or, it's m7b5 down a m3rd. And I never really thought about using it that way before but it works beautifully. The minor 3rd motion thing never ceases to amaze me.

Major 3rd motion is very cool as well. The "In a silent Way" secret chord progression. Also the 'main' key centers of the 1st 8 of Giant Steps - B, G and Eb

This message has been edited. Last edited by: klasaine,

Okay, I'm gonna go after this one I think. Sounds like something that has given you a LOT of mileage.

I have actually played a lot with "minor 6th." chords. I know there's gotta be a better description. But, they're R b3 5 6.

I have gotten there, from playing Blues Scales with the M6 subbing for the b7.
EX: Over A7, I mightplay A C Eb F#. Often adding the Major 3rd., and the 2nd.

But seeing it as an F#m7b5 is nice. And all those uses you've mentioned........