You can use just as many colours as you like, totally 640 grams. My blanket is 75 * 75 cm and is crocheted in Mayflower Cotton 8 Junior with needle 3,0.

Here you can watch how I made the blanket - https://www.youtube.com/watch?v=hQOEYgBfH9M&t

The pattern comes in both English and Swedish. Mönstret finns på både engelska och svenska.