WessB, I love Sweet Potatoes on the egg!!! I just put on with whatever is cooking for about an hour. They get really soft (and burn marks on the skin from being cooked directly) when they are done. Then cinnamon/sugar and Butter on them. Man it doesn't get any better. If I had to guess the time and temp it would be 350-400 for an hour (but honestly just cook them till they are really soft). Cook it with a spatchcock chicken and they will be done about the same time.