How do people play the Witch Hunter Praesidium Protectiva rule that states that it may only be used against one "opponent" per turn? Does this mean one model or one unit? Sounds like one model, or it wouldn't be much of a disadvantage. Would any models rolling to hit against an IC with a PP need to roll separately so that it can be determined which model the PP save is best taken against? This seems to me the most sensible interpretation, but it seems quite vague. Or maybe I am missing something entirely..