CV Notes/Tracking/Accuracy: Do you have a multimeter/voltmeter, or something like a MORDAX DATA or an Ornament & Crime that you can use to see what voltages your KSP is putting out?
MIDI/USB/POLY: I can't speak in depth to your issues with the polysynth/USB thing (but I'll note that "USB hosts" and "USB devices" are basically fundamentally different - computers are hosts, keyboards/flash drives/the keystep/pro are devices. Worth researching and keeping in mind, if you're not very familiar. Also, not all USB devices "that do MIDI" are equal - some are "MIDI Class Compliant" devices, which appear as MIDI devices to the computer/host. Others aren't. And, I have no idea if the KSP is Class Compliant, or custom - but if it's the latter, there's not much that can be done, other than inserting an intermediary MIDI/USB device.)
You may do well with a cheap USB/MIDI adapter cable, if the thing you're trying to connect to is a USB *host.* With the Organelle - the *new* version has both MIDI and USB, but that doesn't help. Seriously, though - go to the Guitari forums and see what USB MIDI adapters people have been using - there may be a ~$15 USD fix for that.