ME3: unlocking Rebellion and Resurgence pack characters and weapons?

How do you unlock the new characters and weapons in Mass Effect 3's DLC packs? I've seen plenty of other people playing with them, and I can see the new characters greyed out in the selection menu, but after buying a ton of those annoying random loot packs I haven't unlocked even one.

Are these only found in the 99k packs? If so how many of those packs do I have to save up for to get even one to turn up?

Do you have to play a particular game type? Does having existing characters up to a certain level help?

Solution 1:

Most class unlocks are considered 'rare' so buying spectre packs are the best way of finding them since it guarantees a rare. If I remember correctly, the 99k packs guarantee 2 rares so may be a good option as well. Whether or not you get one of the ones in the DLCs is pure luck since there are many rares in the game.

Solution 2:

I have unlocked 2 characters so far. I have purchased about 10 premium and spectre packs each. If you strictly want to unlock characters, the best chance and bang for you're buck would be the premium pack (2 rares for an extra 30k than spectre). I usually stick to silver maches which usually gives me about 100k every 3 missions.