The biggest difference is you need to get a lot of stackable cables. Serge stuff is really designed for stackable and cross patching, audio and cv is the same and can be mixed unlike Buchla. Just patching in a eurorack type way with an occasional stackable, won’t get you there, without stacking. That’s the biggest difference between 4u and Euro - banana cables. Everything goes everywhere, inputs and outputs can be mixed, in some cases, audio and cv is treated the same. It encourages you to create cv and audio feedback patches. The other thing is many of the modules can be used as oscillators. Envelopes, Filters, Wave Multipiers, Res Eq, SSG can all be used as sound sources. Pretty much the whole system is a source source in 1 way or the other.
I look at the CV side first and the arrange the sound around the CV. I work backwards when patching Serge compared to Euro. I start with the DUSG’s, not the oscillators. So for me, it’s about the control and manipulation of the CV, triggers and gates. The finer control you have of that, the more interesting sounds are generated, even with the most basic oscillators. Boring things like CV mixers, attenuators, logic, envelopes are more important than the oscillator. The heart of most of those patches start around 4 envelopes being cross modulated.
There’s Randomsource Serge modules which are all identical and sometimes enhancements to the STS 4u, and superb quality. The pcb’s and components they use are a cut above many manufactures. Serge Tcherepnin is the chief innovation officer since November http://randomsource.net/Serge_joins_RandomSource.pdf . I have built a VariQ, Wave Multipliers, Variable Slope, Res Eq eurorack modules. So that would be the best way. Everything modulewise is there at Randomsource, except for the analog Freqency Shifter (Cwejman FSH-1?). So the biggest difference is the the way you patch it. I would focus more on the CV modulation side.
The patches I did for the album are based around, 3 x DUSG panels (3 Maths or 3 Rampage that go into audio range). I just saw Frap tools Falistri and that looks to me, very close to a DUSG also. Also I use an SSG (use a Sample+Hold+Noise module or Toppobrillo Sports Modulator is superb), 3 x VariableQ (State Variable) filters that self oscillate and are pinged (something like a Twin Peak Filter, 3 Sisters, Toppobrillo Multifilter). A noise module with pink and white noise out like Quantum Rainbow v2. Wave Multipliers and a ring modulator. I also use a Crossfader VCA and have 2 different patches on either side that I fade between for shifting changes. It’s something I do a lot when playing live. A CV mixer for mixing all the DUSG envelopes - something like 4ms SISM, CV Tools, Some sort of touch controller that triggers a sequence of voltages, like 2 x Pressure points. A logic module with at least one XOR output. You need very clean, high spec VCA’s with a lot of gain and headroom.
Hope that helps
