As some of you may know, I have recommended mixed proteins of just taking one. What I mean by that is why just take whey or Soy when you can take one with Whey protein and Micellar casein and Egg proteins together. I found an interesting article in the Journal of the International Society of Sports Nutrition, that goes into this. I posted this in training and Nutrition, but read about guys that can't weight. If you’re having trouble gaining muscle and size, the article also goes into the amount of protein you may need.
One caveat, it is a bit long, but it is free and worth the time to read in my opinion.
and read the article: . Contemporary issues in protein requirements and consumption for resistance trained athletes.