What? Fishing the wall? What kind of sorcery is that? Just kidding! I love old work for that very reason. Getting the wire from point A to point B cutting into and fishing walls. I’ve even amazed people to the point where they ask “how did you get the wire there?” But I see what you are saying - the one hole method. If anything you should be fine putting one on one side of the stud bay and the other on the other side. If anything just to give the wall board or plaster a little more stability in between the cutouts.