I have quite a few different meringues that I will be making but only so many fit in my oven at a time. Since they bake for so very long do I need to keep the meringue batter refrigerated while batches are baking? Will it change it at all? TIA :-)

Do you only have one shelf, not sure what you are meaning in I only have so much room.  Utilize the shelves you do have and if you need to you can move trays and swap positions of the trays. You can keep the meringue batter out however, rewhip before you use them for more trays.  Good luck!