i personally like the aesthetic having a bottom most rack for 1 off triggers, sequencing, and other melodic units, then filling in the rest of your voice chains, and whatever else you may want, wherever it will fit into the rest of the case, so that you dont need a keystep or or midi controller or anything like that and can just play the case as is and do most of the performance on the bottom most rack. im no expert, but thats just the way to build a case that seems most aesthetic, to me. you can look at my fantasy 4 case 'ttest ssystem' where i tried to apply this as best i could, and yes, i did quasi intend for them to work somewhat seperately, too. im just getting into modular. i decided to build fantasy systems on here for fun.