Depending on the cables you use, there is a chance that the different lengths might load the amp differently.
Compensating for different speaker cable lengths
The minimum speaker cable run is 16' to the right channel of my system, but only 8' to the left channel. If I add a second 16' cable in parallel to the right channel, this will equalize the total resistance of each channel (although inductance and capacitance would be different). Alternatively, I could simply use a single 16' cable for each channel, or purchase a 16'/8' pair claimed to be insensitive to the differences in length (e.g., Ocos or Transparant). What is the best general solution to this problem relative to soundstage imaging and frequency response?