The recipes are made to fit the 24oz original tall cup unless otherwise noted. The recipes in the NutriBullet Rx book are for the smaller 30oz cup.
"Fill to the Max line" refers to the max line that is marked on the cup. If yours does not have a line then be sure to leave plenty of room at the top for the ingredients to expand and allow them to blend smoothly. Liquid measurements will vary, but are usually about 1.5 cups.