Tim, you really should give Kerry a call about the fencing. He will be able to give you the appropriate guidance on that.
If you ask me, I would say there needs to be another fence between the track and even a single strand of barbed wire. I don't even like barbless fence wire. The problem is that single strand wire too easily finds itself in between the helmet and neck brace, or wrapped around a leg, etc.
Some tracks will weave a strand of barbless into the top and bottom of field fencing to add strength, that is fine as long as it is woven in and cannot wrap a driver up.