How many eggs can one place in the hatching tray when it comes time to lock down? Do you leave them upright or lay them on their side? I had less than a full tray of eggs and laid them on their side, but am now fearful that they don't have enough space to get right out of their shell ... Just wondering if I should tip them back upright. I do prefer to hatch them laying down, but not sure if this is going to work!