Ever since the Tower, Rhys, presumably working in conjunction with Eliot, has been working on improving the wards he's been building since he arrived in the City. At this point, given his empathic ability, studies, and practice, how effective a ward is he able to build against demons?

Understandably, anything that he can create against the shadow demons will be extremely time-and-energy intensive, but how much progress has he been able to make in that regard, given his experience with their attacks?