Rough analysis on 4pT12 vs 2pT13:
15s extra seconds of Zealotry means at best 15 extra HP every 2 min, which averages to 1HP every 8 seconds, provided you have a 3-second CS, which isn't true most of the time, and that you have very low latency. A more realistic approach would be 12 extra HP every 2 min, averaging to 1 HP every 10 seconds.
Considering Judgement has a 8-second CD and that you should be using that as often as possible, I think it's pretty safe to say that 384 + 397 T13 will be superior to 2x391 T12 breaking 4pT12. Even if you consider that Judgement will sometimes be pushed for higher priority spells, it should stay below 1 Judgement every 10 seconds. This doesn't take secondary stats or socket bonuses into account, so replacing items with different itemizations could be a further DPS gain or even a DPS loss. Fight length also plays a role here.