If I take a 200L Fuel tank of a commercial vehicle as shown in the image which has Say X, Y & Z as its primary dimensions, Is there a way I could tell if we would need baffles or not?
If I understood your question, it could be answered by the use of the fundamental subject "rigid body motion". Width, across the motion direction is not matter. The height and length along the axis of the motion are critical due to the acceleration. Hence, for extra wide width tanks, we may have no problem.