Personally, I would hesitate to double the recipe for fear of the center not getting cooked all of the way through. With something such as a quiche or egg casserole, could you not make some pie-tin-size in advance, keep them in the refrigerator until serving time and then microwave them just before plating? Making as much in advance as possible might give you the organizational edge that you need when feeding a large group.
BTW: Congratulations, and do try to enjoy yourself - or at least take a deep breath once in a while!
Never trust a skinny chef!