Lactose is unfermentible sugar, so it shouldn't matter when you add it. I add at bottling. I just boil it with my priming sugar, let it cool and add it to the bottling bucket.
I have made several batches of Green Tea Ale. I steep 6 green tea bags in a half gallon jug of cold water for 90 minutes (shaking occasionally). Then I remove the tea bags and dump the half gallon of tea into my secondary.
I just brewed a Dr. Pepper Porter yesterday. Then I found this forum today. I didn't realize that anyone else would be interested in such a crazy idea!
I just took one of my robust porter recipes and replace some of the sugars with the Dr. Pepper, and reduced the amount of hops to allow the DP...