This will become a 9u case filled with modules that expand/support the Verbos System and the Shared System.

Expert Sleepers ES-8/ES-3 provides envelopes, LFOs, Arps, sequencers etc. with Ableton Push 2 for knob control.

Also includes Eurorack pedal versions of Retro Mechanical Labs Electron Fuzz and Hyde Filter which connect via the Retro Mechanical Labs GPI. There’s also a Make Noise Mysteron, STO, and Moog DFAM.

A Roli Seaboard Rise connects via Softube Modular and sends CV thru Expert Sleepers/Apollo to talk to the system.

Not a bad set of choices for an expander cab. One thing I'd suggest for your open space would be another complex function/envelope generator such as the Intellijel Quadra + Quadra Expander mkii, Sputnik Quad Function and Trigger Generator, or the Doepfer A-143-1 (if you can fit a 50mm depth in your case). Since the Shared System will have a Maths, having a different strategy to create complex envelope/modulation curves might be an asset. Also, if we're talking about the original Shared System, you might consider updating to the Rene mkii, as it works together with the Tempi module to unlock a bunch of cross-communicated features. Keep the original, though, as having extra sequencers should never be a problem.

Haha! I was JUST reading about the Quadra + Expander over on Muffs because I agree a little variety here is good. I like the idea of going that direction. I lose extra attenuverters (and slew?) but I can get the 2hp or doepfer versions or Function to replace. The Verbos Multi-Envelope will be coming soon as the first expansion to the Verbos System too, so 3 interesting flavors will be available with each system standing on its own.

Still I’m quite interested in a Batumi even with the ES-8 which has quad LFO’s available. Mainly because I love sliders and the visual feedback.

Thanks for your input, it really helps!

Make sure to leave 3hp for the Batumi's expander, Poti. This adds some useful waveform selection and sync functions. As for slewing, you'll have part of the Maths to use for that, when necessary, but a useful addition for that might be Ladik's C-012, which is a dual slew lim with switchable up/down/both CV detection.