Yep, divider goooood...but choose the more capable A-160-2 instead. This gives you not just the usual suboctave division, but an integer count + divide by primes. Then, by adding a simple Boolean logic module such as Doepfer's A-166, you can combine the outputs from the divider + your regular clock to create more complex crossrhythmic gate patterns. Even better would be to add a comparator to this lineup, which would allow you to track voltage curves coming off of the Maths or the Black Modulator or EG to generate a gate pulse when the voltage crosses a determined level. Put this all together with the logic gates, and the rhythmic timing aspect will be bonkers!
And do put the A-138p and o back in there. The Quadratt is great for summing down the VCOs or attenuverting CVs, but it's not much on audio when compared to a proper stereo performance mixer. It's more of a "utility" mixer, plus offset generator and inverter, while the 138 series is very much audio-specific and allows you to build up a stereo image for your stereo Line Out. By feeding the A-138o to the Black DSP, then going from there to the Line Out and using the DSP's wet/dry knob (or CV control over it) to balance your stereo effects against the dry mix, you'll have loads of control over global effects...and STILL get to use the AUX send/return setup in the A-138p/o combo for something like a mono delay (something simple but with CV, like a Dreadbox White Line Echo) that you can mix in on a per-channel basis. Pretty cool, pretty neat!
But yeah, this is rapidly approaching "button 'er up" time. Think about those last two ideas, then I concur with Garfield...this'll be a damn fine system!