Tip #3 - There doesn't seem to be any way to avoid instant wipe after 3 charms in the final phase. For this reason it is suggested to keep your LB for this phase and use it after the second charm, using it early can cause you to force the boss into instant wipe early (whether this is a bug or not I'm not sure, but if the LB doesn't kill her she may skip any more charms and go straight for instant wipe).

I hope this helps groups with the mechanics of this fight. Just remember, this is not strictly a DPS fight, it can be controlled and there's no reason to rush kills on adds as you will still survive Blood Rain with an add eaten at or below 40%.