I did a lot of up front calculations, but the final circuits were adjusted by ear. I am pretty pleased with the result, enough to go ahead and redraw the PCBs. I have decided to place the two VCAs on a separate, tiny PCB, which can be reused for other projects. I will also try to fit all parts on a single PCB instead of the two that the initial design uses, but this probably requires me to use SMD components again - the prototype uses almost 30 op amps and more than 50 resistors and takes up one and a half proto board :-)
The result is quite good, although not as good as I initially hoped and dreamed about. I am still impressed with the result though, especially at lower frequencies - it will make one hell of a bass sound. I may try to make a "computune"-style automatic tuner, to keep the oscillators better synced. I will also add a chorus, filter and perhaps distortion module, but for now I will focus on making the controller PCB.
Before protoboarding this circuit, i finished the 8 oscillator module, complete with separate fine tune pots and 8 CV in / 8 saw out connectors. It looks very cool!.
I shot a few videos for a friend of mine - the quality is crap but it illustrates how things work: