Sorry for the late reply, check your PM for contact info :)
So what I’ve focused on in my Strega-ish patch is that grating, raspy sound;

OSCILLATOR:
Without filtering and delay, the Strega core sounded is fairly simple to my ears (=oversimplification, cause audio-rate feedback is not possible in ZOIA as it is in modular world).

I took 2 oscillators – a triangle with a 60% duty cycle as the core and a sawtooth tuned a 5th above it – but both controlled by the same pitch info, so it’s basically still a mono-synth. They go into an Audio Balancer so you can blend between them, and there’s some VCAs to create some FM feedback from one to the other. All of this blending and FM’ing is controlled by a macro-value module, the “Tone” control, which sweeps from a nearly-clean triangle through some flavors of FM-rich overtone blends to an almost clean sawtooth (makes it a very fun parameter to modulate!). Oh, and the pitch of the oscillators goes well into the negative values, for strange pulsating machinery sounds.

INTERFERENCE:
To me, one of the things that makes Strega interesting is this single ‘interference’ signal that can be applied to different sections of the circuit, so I tried to capture a similar feeling (though without the feedback of the rest of the circuit BACK into the interference signal, which is hard in ZOIA as compared to analog circuits).

I use 2 Random modules and extract a bunch of modulation signals from them (by multiplying, slewing, etc.) that are tweaked to modulate certain parameters; Pitch, Tone, VCA (that one kicks ass!) and Filter cutoff each have their own flavor of interference that can be turned up.
To add grittiness to the oscillator(s) there’s also use a Noise module -> bandpass -> VCA -> Oscillator FM input, where the filter cutoff and VCA are also modulated by those same Random modules (i.e. all “interference”-related modulation originates from the same source), and controlled by “Interference” macro controls.

DELAY / FILTER:
Although the ‘triple asynchronous lo-fi delay lines’ from Strega sound pretty cool, I think I’d need a dedicated patch (CPU-wise) to get close to that effect, so I kept things simple here.

The main filter (before the delay line) is a simple low-pass SV Filter.
Then I just have a short-range Delay Line (from ~2ms for Karplus-Strong to ~1s for normal delay) with a fixed low-pass filter in the feedback path (cause I’m out of CPU to modulate it)

PATCHABILITY:
I like the strange and harsh sounds this patch is capable of (mainly the combo of the oscillators – with lots of FM and noise – and the “Interference” modulation of those parameters), but a big part of the fun for me was to find a way to have this patch be playable or ‘patchable’ like a desktop mono-synth. I built that looping AD envelope from Strega, and you can route MIDI keyboard and gates to a bunch of stuff. It’s very fun!

Well, not sure of this helps, but look me up on Facebook for easier dialogs.
Cheers