I have a question about Cellini portafilter basket size vs coffee weight. I've read that generally speaking in order to pull a single shot you should start with 7 grams of coffee and a double requires 14 grams. However, I noticed that when I weigh the coffee on a scale, 14 grams doesn't do much to fill the double shot basket of the Cellini. When I tamp the coffee it sits well below the line on the inside of the basket. I checked the scale and it's accurate, so it seems to me that the double basket requires more like 20 grams rather than 14 in order to pull a double shot. I tried pulling shots using only 14 grams and it just doesn't seem that the basket is made for such a small amount, but what do I know. Am I way off? Any advice would be greatly appreciated.