If she responds well to just one in the ring that's great. I myself don't like free lunging. I feel you gain more control and teach a little restraint on their part when they know you are in control. Sometimes when they are free running and not reined in a certain area I have seen them spook and try to scale a round pen wall. One such incident the horses chest was deeply gashed. If your horse is already familiar with the pen it is likely not as much of a risk.Good luck with her training. It builds a great bond with your animals to work with them on a regular basis.