Has anyone found a good way to get the runestone for fragments? I always seem to get really unlucky I guess. I've got 18 ranks and I only have 6 Potter runestones left and I've only managed to get 1 fragment. I'm worried the second part of the event in two weeks is going to be difficult if I've already gained most of my ranks already. I've been mostly running Ruins IV, V, and Tower 1 challenges with it.