The best way to use the auto-tune is not to! And that's what I do: I do not use auto-tune!
Even with an assignment, I take over, I find a freedom and make the idea my own, and that's where you get the sense that the essays become something very different than the original subject. Assignments are great, though - they test your mettle, your spirit and resilience. All of sudden you drop in, you don't know anything, you're vulnerable and available.