I've seen that some of the incubators have manual egg turners (pvc pipes with a carton attached) to turn the eggs. My question is this: if I were to use my hand, I would turn the eggs 180 degrees. However, with the egg turners, do they only slightly rotate back and forth... like, a pendulum sort of, just lean left... then lean right.... ya know? Is that ok? or was I missing something in those designs?