Hi @cannc ,
for the final PCB, @lijnenspel can say as he is working on that 
As for the wiring of the proto, it is really piece of cake.
the āhardā it for the pink-0 part, there i just copied the clock reset part from there https://github.com/shaduzlabs/pink-0/blob/master/hardware/pink-0.pdf it is just 4 resistors, 1 cap and one transistor. (they are hidden under the pi on the picture). that said the proto can work without pink, this is totally optional.
As for 20 cv outs : it is dead easy! ground, 3.3v and SPI (mosi, miso, clock, and device select) between the pi and max11300 board. (it is the coloured wires you see on the pic). Then the board itself does all the job, and i have the outputs of the max11300 board directly wired to the jacks, one by one. At this level this is more electricity than electronics 