dasdoing
Major Contributor
Actually, no I didn't but John kindly added an option to sum the mic responses for virtual balanced second mic to REW for me. Still, the results are suboptimal although very close to the actual mix. I will work on your suggestion now. Thank you so much for this.
you really just have to think of the mixer like a mixer. the mixer has several inputs and a stereo output (which becomes a virtual input via loopback). two mono inputs centered will produce a copied mix on both channels (with gain shared). panning both to one side will add them both on top of each other gainwise (might clip).