Various suggestions

[Mupp]

GX-80 is good, but I feel it would be improved through the addition of calibration settings. My old Yamaha synths CS-50, SY-2 etc, are in better tune than this. The sound of the GX/SY could use a bit more attention in future updates. The GX-80 GX filter doesn't behave like the real type. Needs some more work. If you don't have access to a GX-1, I am sure you can get an SY-1 or 2 for comparison study. Perhaps model the GX/SY style VCOs. In addition, when switching in the GX filters, the LPF should go before the HPF.
Keep improving it, it is a good effort. I am sure it can become great. Thanks