Solid advice! Thank you so much. Take away points: (1) consider building a 6U or 9U case from the start; (2) ax the second A-111-6 for a second or third VCO for variety; (3) Consider a couple EGs instead of Maths; verify the mixer's capability for input and output.
Yeah, I can see how that would be a good bit better, just the kind of direction I was hoping for. Thanks!