Spider wing help(so close)

[Niley]

Hello
I was a bit bored today(again), so i went to naxx 10 with my 5 man group, just tried spider wing.
I was able to down pretty easily this 2 bosses:





On maxenna i was wiping around 35%ish, Sort of like this:




Anyone has any ideas for this boss? maybe something i missed?
Im, fine with doing cocoons, and dealing with spiders and her poisons. Problem is that with just 5 between all of that stuff and healing(lots of healing) i have very little time to dps. Ive tried few different ways to position, but that didnt help either....
Does she spawn spiders and her cocoons below 30%?
halp!