/vp/, Please help me out. I'm not very familiar with breeding, and I'm learning the basics.

I want to breed a perfect Adamant Onix, and I was wondering if it matters if I should have Ditto have the nature or Onix?

Also, which one should have the stats? Should it be Ditto so I can reuse it over again?

Lastly, do I need to do anything as far as the IVs of the parents go? Or do I only focus on the IVs of the egg when it hatches?