I have little question, how did you managed to remove plague from you? I thought you need to dispel it? Or am i mistaken?
And is it true that you dont need 11/12 HC save to pull LK HC? I thought u need to kill Sindragosa, PP, Saurfang and BQ on HC.
Necrotic plague got a duration and you can just wait it out each time it gets applied.
You can do 11/12 on normal 10 and then switch to 25 heroic.