This would be great for A/B-ing. I too use a summing mixer and have found a great solution to track ITB (with zero latency on the rest of the tracks) while retaining the outputs to the summing mixer. As you probably know, constantly changing the outputs on each track takes forever.
If you right click in the console window, there are two options: "Enable listen bus" and "Solo through listen bus". "Enable listen bus" can always be on. When tracking, I use the option "Solo through listen bus" and simply solo the tracks I need to hear when recording, and they are then routed straight to the main out, not going through any conversion or analog gear. I then also activate the metronome on the listen bus. When mixing, I deactivate the "solo through listen bus". Hope that helps, it really was a game changer for me!
