It's an interesting question for sure!
Maybe you really should have a look at NLC Triple Sloth: it's a slow to very slow chaotic lfo module. The slowest cycle can be 30-40 minutes: very well suited for slower evolving pieces.
Similar modules that might be of interest: Joranalogue Orbit3, DivKid Ochd, SSF Ultra-Random... and many, many more.
A basic S&H module - Wogglebug Smooth, TipTop Buchla 266t... - into a channel of Maths. Apply offset and attenuation, mix with another Wogglebug voltage... can be a super nice signal to work with throughout the patch. Wiggle some controls from time to time, change the mix.
Seems like you have a nice selection of modules to work with. Ask yourself, which elements in the patch you'd like to modulate over longer periods of time. Look at what you have, then buy some more utilities.
Maybe a matrix mixer, a polarizng (ALA Monocle), a sequential switch like the Befaco Muxlicer, more litte mixers, mults, logic...
As a beginner in Modulars, i would have difficulties to define my system as you mentionned.
I own quite few (Math, Wogglebug, Cloaks, Beads & Strakal Orsel, Skorn Orsel) & Intellijels, Behringer modules.
Any patch i do works on its own and can/may modulate, surprising me. I bought modulars so to fill some free hours on our radio calendar, meaning it would be great if my patches would start with some modules which would modulate and Change the normal behaviour of the patches, as bringing some chaos in it. I am not searching at all for compositions, more to develop a kind of improvisation machine which would play by itself, developping and ever changing sequences on a long period of times. (direct English written, not my mother tongue!)-- Vikinge