How many calories and how much protein do you want? Serving sizes only matter in the scheme of your overall nutritional plan. If you don't have a nutritional plan, what are you even doing messing with supplements? Make sure your priorities are in line.
I personally love Sythna 6 because of the taste and because it has fat and fiber and slow digesting protein along with the standard whey. Helps me get more calories for bulking when all I want is protein shake, and the taste is amazing so it is enjoyable rather than a chore to drink
I have a single scoop for breakfast along with my cereal and milk. Seems to give me enough energy for a morning workout an hour later. At a different point in the day, I make a blender shake meal which tastes amazing:
16 oz 2% milk
21 grams honey
60 grams quick oats
33 grams peanut butter
1 scoop Chocolate Milkshake Syntha 6
935 calories, 37 g fat, 102 g carbs, 52g protein