So, I created two racks with a matrix mixer inside.
In the first I swapped Brains with an original Plaits to gain 4HP.
Here I use the Bear Modules Matrix Mixer.
ModularGrid Rack
In the second one I keep the Brains (I like the display) and go with an AI Synthesis AI008 Matrix Mixer,
which I think should be ok for my little case. So I would prefer the second option.
I like to keep the Black Stereo Mixer because I love it :)
ModularGrid Rack