Sorry in advance, this will look entirely like a sales pitch - but it's unavoidable!
I can honestly say that there is not a single academic/commercial resource that I have ever seen that truly follows the McKinsey format and that I could recommend (I am obviously excluding PL coaches, who are often very specialized and know exactly what they're talking about).
This is not the answer you're looking for, I know. However, it's important to know and remember so you're not being mislead by what you're seeing.
My advice for McKinsey preparation is always to get some professional coaching with a former McKinsey interviewer as part of your study plan. They will be able to provide you with real cases and the insights needed to succeed.
Let me know if you'd like to learn more. I used to be a McKinsey interviewer and know exactly what it takes.
Best of luck!