I can’t figure out the dual reservoir either. Pictures made it seem like the big section is the out and the smaller one is the return, but the bottom loop seems to reverse that. I know that the loop will equalise temperature, it just seems weird to have say gpu output going straight back to the resHi there just about to start some runs but realised I am not sure about flow direction in the distro plate. Will upload a picture.
Looking at the pictures on his site I’d guess that the lower left is the out to the cpu, the one above is the return. The two right channels are for the rad.