Personally, I like the breakaway cable adjusted so that it will energize the brakes ONLY in the event of a total separation of the vehicle from the coach. I do not want the abrupt stress of the fully braked vehicle on the safety cables/chains. IMO, the chance of the cables/chains being yanked far in excess of the rated strength is too great to allow it to happen.
The electrical cable, IMO, should be long enough to avoid being torn loose when turning, but short enough that it will never drag on the ground. Mine is not coiled, so it is taped to the towbar. It works for me.