I know it is irrelevant really but I noticed a lot of people stating the middle eggs turn more than the outside eggs. No they wouldn't. They would turn less. It's very simple to work out why too. They turn based on the rotation of the egg turner. If the egg turner makes one rotation, the eggs on the outside will have completed one rotation. The eggs on the inside in comparison would have completed one rotation. You might say nonsense. But that is how it is. When the dial on a clock goes round, every hour it makes one rotation. If a fly is sitting on the dial as it goes round it is irrelevant if the fly is sitting on the end of the dial or near the middle - it will have made one rotation in an hour - but f the fly sits on the very end of the dial then it will travel a much bigger circle than if it were sitting right near the middle of the clock.
So if the outside eggs travel a further distance for each rotation and all eggs go though the same rotation then for each rotation the outside eggs travel further and thus are rolled more.
But it is irrelevant from a practical point of view as if you use smaller eggs, the smaller egg diameter will mean it will actually roll more per distance travelled than a big egg and thus counter the increased rolling distance the bigger eggs make and will probably be turned roughly the same as the big eggs. Even if one were to use big eggs in the center the slightly less turning of the middle eggs would be negligible as automatic egg turners are so constant even turning throughout the night.