200 jewels? It's taken me a long time just to get 13
As for the mythic packs, I look at it this way. I have 75 out of the 134 existing mythics currently. Thats about 56%. So for 400 jewels, I might expect to get one dupe and one new mythic (?).
I had 78 mythics and got 3 new mythics, avaricious dragon, kalitas and demonic pact. best 450 crystals I've spent for a loooooooooooong time