I would skip the small case and go straight to the larger one - this is probably almost unusable for what you want - audio levels will be wrong for starters and there is no modulation or utility modules to leverage the effects you have into anything other than static effects - unless you turn knobs manually - which is a great idea, but you loose the interesting parts of modular - complex modulation

I'd also consider mono/stereo issues

Personally I'd always want a vco and lfo in a modular, even if it were predominatly for effects - something cheap and analogue will do nicely - doepfer basic vco for example!

you need mixers, vcas, envelope generators etc

"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