Parallax only requires you to know the separation and angles (and fields of view) of the cameras. Two parallel cameras at 1 meter separation and 90 degree field

Parallax only requires you to know the separation and angles (and fields of view) of the cameras. Two parallel cameras at 1 meter separation and 90 degree fields of view are fine. You could change the separation and angles every frame, if you wanted, as long as you always did your calculations from the correct position data.