We have him at around 30% after the two nests that spawn together (9 & 10), and after dealing with those two we just zerg it down.
Out of curiosity though, don't you guys who take only 8 nests have insane amounts of Juveniles raping your raid by the end? The 9&10 nests are pretty easy and you get like 6 Juveniles just from them alone, not to mention the following nests.