Well, I think the only final step is Liebman and Beirach.
TBH I'm still in a retro-mode, permanently, just doing Elmo Hope and Bud and Herbie stuff as far as voicings — that's just where I'm at, and I'm happy to be there.
But the systematic method really begins and ends with the Liebman and Beirach "textbook," as far as I ever heard. It's the basic things about upper structure triads.
The nice thing about that book is that it doesn't lock you into the (ascending) melodic minor mode dogma — for me, the modes of the harmonic minor scale are just as, if not more, important.
So, just practice harmonic minor modes, transcribe, and don't do jive stuff, I think is what anyone would agree on.
ETA How much can one say? WTH do you want to play other than sound like some sax player wearing a funny hat in some "funk-jazz" group? If you want to do that, then transcribe it. If you want some deep theory of upper-structure triads, well, then, good luck: there isn't one.
EETA Well, if you're just starting out, or even if you're not a complete beginner, what's wrong with the way everyone else came up in improvised music? You have the recordings, and you have the keyboard, so, put it together. Transcribe. Rinse. Repeat. Maybe it took Coltrane thirty years what you can do in sixty, or maybe Monk did it in fifteen years where it might take you one. They say Monk would spend fifteen, sixteen hours just plinking out a melody of some corny tune on the piano. Doesn't matter. If it takes forever, then who gives a ***?