I discourage the use of a numbering system because they can become confusing, but for the purposes of the drivers I would use the terms "home, middle, far" and "left, center, right." However, this system works properly only for the drivers, and I would suggest either a single system that is universal or an additional system for the audiece and scorekeepers to use, such as what i suggested
here. However, if this is in terms of drivers only, I recommend using option 2.
_Alex