If this is supposed to interface with a Max patch, it's awfully limited. And a lot of that is directly attributable to trying to use too small a cab for the build. As many of us here have noted, trying to use these "beauty case" builds is fraught with restrictions that actually impair the synth's capabilities and performability. They're fine for "mission specific" rigs, but trying to build a full-on Max destination in one is asking for trouble.
First thing I would suggest: remove the ES-8 and go with an outboard interface. Any DC-coupled audio interface works, and I and a couple of others here use the "obsolete" MOTU 828mkii as that. By going with an outboard interface, you can easily expand via various interface I/Os, plus the 828mkii isn't considered "optimal" for recording these days, so they come in for cheap. And Ableton CV Tools has really good DAW integration as...well, it's part of Live in the first place, so there's no need to hunt down plugs, screw excessively with interfacing protocols, and the like. Also, since it's NOT in the cab, you'll be more likely to want to use it on other CV/g/t-capable synths.