I didn't put any measurements because I don't use them much.  I just kinda do what I think I might like.  Rub sweet potatoes with butter and bake until done.  If you want, you can do this step in advance and put in fridge until later.  Peel potatoes and slice about 1-1 1/2 inch thick.  Cover bottom of baking dish with brown sugar and dot with butter.  Put sliced sweet potatoes on top and put a little more brown sugar and butter on top.  Sprinlke with cinnamon and bake until brown sugar is bubbly and the sweet potatoes are warmed through.