Idea for the system is to have modulation options for arps/leads to use in Ableton tracks I write. The goal is to have useable, clean ideas that I can drive or affect before committing to tape. Pretty fun system so far!

In a very small build as this, it's important that EVERYTHING have an actual function. As such, I would suggest deleting the o-scope tile and replacing it with a 2 hp blank and an Intellijel VCO 1U so that you can have at least one dedicated LFO to use alongside the Maths. I also pulled the headphone preamp and the mono reverb so that you can have a stereo FX processor that does more than just reverb. Other than that, congrats! You managed to create a build that CORRECTLY utilizes the space in a small cab. And this looks like...
ModularGrid Rack

Thanks! Good suggestions, I actually really like the changes you made here. Will look into that!

I would suggest replacing Maths with a Schlappi Engineering Boundary. It can do most of what a Maths can do in an easier to use and smaller form factor. That would free up 8HP which opens you up to a lot of options.

It's a cool looking module, but I already own a Maths and was looking forward to really digging into it! Plus in terms of modulation, it can accomplish what I need it to do, it's a pretty important part of this build!

Maths is an extremely versatile and capable module, the size of it is its only downfall. In a small system like this every HP counts. In the end it is your system and if you already have the modules and they are accomplishing the tasks you want, keep going and have some fun with it!