That Befaco mixer bugs me...you do know that if you mix the -MIX and +MIX outputs as if they were L - R stereo, you'll get some hellacious stereo mis-phasing issues, right? It looks like this is intended as a final output mixer in the revision, which is why I'm pointing that out. If you're trying to put a stereo mixer in 6 hp, have a look at Happy Nerding's PanMix Jr. instead. Mind you, the Befaco is useful for getting simultaneously normal and inverted signals, but this is something that's better suited to modulation signal mixing, where the normal + inverse outs would actually be far more useful.