Just finished this up. As others have mentioned the fact that mobs kill each, and roam all over makes this annoying. I did have Karg and Martan up at the same time. Placeholders do pop at the 9 second mark for both cycles. Can say for me nothing spawned West of Megan's tower, or below the bottom of the V. Did have a PH spawn almost at the giant's fort, so they do go East a good ways.
As Jessiecuh said, there isn't a unique to any cycle. I saw the full list they posted on Karg's cycle. I never saw ice goblins on Martan's but I wasn't killing his after he popped, and he always showed up crazy fast for me (literally never more than 4 ph).
Good luck to anyone else that does this. The changes made to aggro to stop bards and shadow knights made these things harder than it used to be. I remember doing Quillmane and the monk guy by rounding up everything in the south end of the zone on my wizard and ae blasting it down. Then looking for the correct timed respawn. Was so much easier than trying to find it one by one.