Cables should always be equal symmetry in length considering that you have the model and awg wire the same. Like Dbw1 said, timimg has nothing to do with length mismatch, its resistance. Resistance in a speaker cable subtle to voltage drop which in turn cause signal loss. When this happen, your intitle to hear a few db or less which cause image to shift off center. This is why it so important that you have the same length on both sides.
Alfredo
Alfredo