Maybe Logic Pro X could be used this way to make custom midi tracks that can be imported into the new Korg Pa4x built in SMF (Standard MIDI File to Style converter). I don't know if it would be easier to make your own custom styles onboard the Pa4x hardware, it's editor, or import them via the SMF method because I don't understand enough about the Pa4x yet. I'm talking about self-made custom styles from scratch, not taking existing pop song cover MIDIs and importing them.
Hal