I agree with sweetcell on the crystal. That's a lot. As far as the oats go, you'll get some good mouth feel from the lactose, and could mash at around 154*, although that will effect your FG. If you do add oats, go for 1 lb. After you add the nibs, you'll want to taste it regularly to determine when it has the intensity you want. You ought to get some good chocolate flavor from the chocolate malt, so you don't want to risk overdoing it. I have a stout that's very similar to this one in the primary right now. I forgot to pick up oats from the store, so I just increased my mash temp to get the mouth feel I wanted. I tasted it yesterday, and it already has a pretty good chocolate flavor, so I'll probably be doing 4oz of nibs and tasting it at least once a week.