It really depends on a lot of factors, most notably the direction of the predominate wind and the points of entry of the deer into the food plot.

If the deer aren't in the food plot until after dark, obviously you are going to need to place a stand back in the woods on their travel route, so that you see them during shooting hours.

I am setting up a food plot for next year that will be only about 15 feet wide and 80 yards long. Because the plot will be small and hidden, and I will be hunting during bow season with little pressure, I expect the deer to feed during shooting hours. So I am placing the stand on the edge of the woods in the middle of the plot, so I have a 40 yard shoot to each end. Because I hang my stand high (about 22 feet) and take great precautions with scent control, I am not that worried about them winding me on the way into the plot, plus I don't really know the routes they will use to enter it since it doesn't have any food yet.