Drew, let me start by saying "I don't know."
That said, here's my opinion:
If it cranks counterclockwise, 2 o'clock is my preference to get it started and "over the hump." Pulling it back is easier than pushing it forward from a stopped position. If it cranks clockwise, 4 o'clock is my preference. Same logic.
Realistically, the guy who worked the assembly line probably put them on within a range, using his comfort as a guide. I would be surprised if there was a hard-and-fast requirement.
I can appreciate the desire to put it in the "right" place. In this situation, "right" could be the result of Chevy's motion studies and customer input that placed it in the most comfortable position. No one knows your comfort better than you.
