I drink 3-4 litres the minimum is 2.5 litres to stay healthy , and its recommended that you dont drink more than 5 litres , and try and spread the water through the day rather than drink a lot all at once as this can overload your system .
I save my first shake / soup till lunch time as I like to have one in the evening , its personal choice and makes no difference when you have them , as long as you have all 3 every day
hope that helps , and good luck xxx