It surprises me that so many people only put 20-40g of protein in their protein shake and actually worry if they should put more than that? You see, there seems to be this myth that we can only digest 30g of protein at one time and the rest will be wasted. Oh no! Better not eat that 10 oz steak!
Where this myth came from, I have absolutely no idea. Anyway, here is what really happens:
If you eat 30g of protein (whey) it might take around 3 hours to digest. If you ate 100g of protein (whey), then it would just take longer to digest, say 6 hours. As a side note, everyone thinks that whey is a fast protein, and it definitely is, but they underestimate how long it will actually take to digest. Furthermore, if the protein is taken with other food, carbs or fat, then it will take even longer to digest, especially with the fat. However, that doesn’t really matter because whey + casein (a very slow protein) is probably optimal to just whey post-workout anyway.
The point is, it doesn’t really matter how much protein you have at one time. What matters is the total amount of protein that you had that day. As long as you consumed 1-1.5g/lbs of body-weight that day, you’ll be fine.
Now that you know this, do not be too conservative with your PWO meal! Your PWO meal is definitely the most important meal of the day (not breakfast!), so you should make the most of it. The reason for this is that during and after you lift, your insulin sensitivity improves in your muscles a ton but not so much in your fat cells. This means that whatever you eat PWO will be more partitioned towards building and/or repairing muscle mass and less partitioned towards fat gain than at other times of the day.
Don’t worry about buying “gainer” shakes or anything like that either. Gainer shakes are nothing more than a variety of proteins mixed with sugar, most of the time maltodextrin. If you want to eat a simple sugar after you lift, then buy dextrose and have that with your protein. The most important thing, though, is that you are having a big fraction of your daily amount of calories PWO and the hours that follow.
P.S.: Some people have said that whey + casein PWO is better than just whey alone. If this is true, it is most likely because the whey + casein will be digesting for longer and you will have protein in your body for a longer period of time after you lift. What I am skeptic about is whether or not whey + casein would have any advantage to whey immediately PWO + whey a couple hours later. My guess is that it would not.