If you want to make some clints, it's generally better to wait until the day a new group of cards comes out and buy a new blood pack in the hopes that you get some of the new cards. The demand for the new cards will be high on the marketplace, so you're likely to be able to sell them at a much higher price.
If all cards of a given rarity are equally rare, New Blood will likely have 4/50 of the new clan. And the optimal Elite pack would have 4/89. So in that light you'd be better off with NB alone when you're hunting for the new clan.
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