Very interesting tutorial.

According to another source Ron Miller : Modal Harmony vol 1,If you take the modal chord formula to be not just replacing the third with the 4th but using the characteristic minor seconds of the mode then you have a complete way of defining modes with just 4 or five tones. I gives you very colorful voicings with a balanced mixture of intervals rather than just stacked fourth power chords (which are great but not the only option).

Lydian 1b557
Mixolydian 146b7
Aeolian 145#5
Locrian 1b24b5
Ionian 1347
Dorian 12b36b7

He also goes on to explain that it's okay to have triad over bass note voicings that may be less definitive than the above but which have enough of the main tones of the mode to distinguish it from others. The idea being that consistent voicing structure going from one mode to another is more important. The tune ' Ralph's Piano Waltz' is a good example of that if you've ever heard it; a classic number by John abercrombie ideal for guitarists and pianists alike!

The other thing I've picked up from him is that modal resolutions in the chromatic modal system a mode always wants to resolve to the Ionian on the same root. You can use this to create modal chord progressions that aren't bound by a key but which still have resolution tendencies.

From another source I've learned that to create variation in a mode over a couple of bars you can resolve up or down with chords built on the next degree up or down in steps, half steps and sometimes thirds but never using a V I resolution. This is to make sure you're creating a modal framework and not a strong diatonic harmonic setting.

What else?.. I remember Ron Miller saying that there is 'plateau modal' tunes which stay in the same mode for the whole tune with maybe a single change or two. Then there is 'chromatic song form modal' which is the way most jazz composers write non-standard chord changes after Herbie Hancock and Wayne Shorter. That's very much harder to do of course! Yet his book explains how to compose in that style. with examples from those artists and also ECM style players; Wheeler, Jarrett, Towner, Weber and others. It's basically a use of impressionist classical harmony techniques in a jazz setting

Alan