"Side by side" or recovering each other, it's up to you, I don't know anything about the screens,
about your projection space setup, if the three screens are physically separated or if there is some soft edge blending, etc…, it remains that :
once you got your three monitors panels windows in OSX, open M8, open AdvOutput,
create three clips (one by projector) in AO window, set each clip to its corresponding output (eight outputs assignable in the right bottom of the window),
"your mission, Luke, is the right three ones to find".
Close AO window. You can set the M8 preview window to your new ratio in the M8 Preferences.
A white line appears in the M8 preview window that shows your new space-work, load a 2400x600 clip on a layer, set it
et voilà !
