Is that really a shuttle system? I don't know it well enough - but I thought it was a single panel? there's one available...
anyway - whilst reasonably balanced in terms of ticking boxes of sound sources, sound modifiers and modulation sources, for me at least there is a distinct lack of utility modules
I know that some people see utility modules as boring and unsexy, but these people do not understand modular synthesis very well - I see modular synths without them boring and unsexy...
Utility modules are the inexpensive dull polish that makes the expensive shiny modules actually shine...
it is in the spaces between the functional modules, where all signals, which are but electricity, can be combined, multiplied and modified, that the real magic in a modular synthesizer happens
at the very least I would want an mi kinks, a matrix mixer, a sequential switch, a quad cascading vca, some passive mults, attenuverters, offsets, a slew limiter, a switched multiple (all of them dc coupled, so that they can be used for modulation as well as audio) - some of which may be a few functions in one module - for example an mi shades or similar
in all probability if I built a rack with these modules in it I would add another 84 to 104hp of 3u, mostly for utilities and to have some space over for possible future modules
If I were constrained to these racks then I would throw out either the Magneto or the Rainmaker (probably the Rainmaker) in order to accommodate the minimal set of utility functions listed above
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities