you can try to use radio - news or mono record to toe the speakers as the human voice must be in center.
not really need to move both side if one side close to wall and another side is open area.
just listen by your ears.
The toe in for the 2 spks.has to be different since the speaker clearance is different. Try toe in 3 to 4 degrees more on the open side first and judge with human voice.