Thank you so much for your reply - it was very informative, and I learned a lot from it!
I'm considering the 6U Walnut Eurorack Case Peter from SynthRacks, which is a powered case available in the widths of 84, 104, 110 and 126 HP. I had a width of 84 HP in mind, but it seems like I will need a larger case eventually, so perhaps I should buy a larger one from the get-go?
I'm guessing something like this is pretty much what fits in the 84 HP case:
I had to take out the ES-5 expander to fit these modules. I wonder at which point I'm likely to benefit from the ES-5 expander.
Does this seem to be a viable setup or am I missing something vital?
How important is a VCA?
Here is a 104 HP version:
Here is a 110 HP version (with a bit of an awkward layout), that I think should contain everything but the VCAs:
I'm also thinking about what the "essential" minimal setup would be here. Perhaps it would make sense to approach this with either Akemie's Castle or Rings in mind, and build up the system from that.