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So I just ran a quick experiment on this. I have a Karrablast with 31 IVs in Atk and Def and a Ditto with 31 IVs in HP, Sp. Def and Speed.
I gave Ditto the Destiny Knot and bred two eggs. Both of them came out with perfect Atk IVs, but the male one had 31 IVs in speed, and the female one had 31 IVs in HP. It seems like it's not only the highest IVs that are passed down, meaning that it'll still take you a couple of eggs to get all that you wish for.