Just reporting in...the MEL9 in the Superego's effects loop is GLORIOUS!
Instead of it playing exactly what you play and trying to duplicate it, it now just plays gentle halos around your phrasing, in whatever MEL9 voice you've selected. You can dial back in some of the superego's synth as well, by using the dry and effect volumes on the MEL9, and then control the overall mix of that against your clean guitar with the superego's dry and effect volume knobs.
You can also put an effect on the guitar such as overdrive, or envelope filter, and it doesn't affect the MEL9 as much...because its the Superego's synth that is triggering the MEL9, and that's built from granular sampling.
You can pretty deftly control with the attack and sustain on the MEL9 and the Speed and Gliss controls on the Superego, just how sensitive the MEL 9 is, so you can control with playing dynamics when the MEL9 sounds and when it doesn't. This allows you to play a completely different phrase on the superego-MEL9 than what you're playing on the guitar. For chord-melody jazz playing this combo is going to be hard to beat for me, because I can be playing something very dense and complex on the guitar, while allowing the MEL9 to highlight things with a stripped down backing track...all done live, and in the moment. It's going to take a little practice to polish it, but its already impressive after fiddling for one evening.