Im about to wire up some rear surrounds in my living room but the routing of the cable is proving to be a bit of an issue. The easiest way to do it is to go from one side of the room to one speaker and then follow the same run to the other. Is there some rule of thumb for a percentage different in wire length? Im running 14 ga to both, one is going to be about 20 ft and the second is going to be around 35 if I do it this way. Is this difference going to be an issue?