OK, so it’s difficult to whittle this down to one question, but when it comes to selecting the protein that delivers the most protein per gram, and NOT per serving, then look for the grams of protein per 100g. It doesn’t matter how much protein you get per serving, this doesn’t give you an indication of the total protein. Naturally, if you use a 100g scoop compared to a 30g scoop, it’s going to seem like you’re getting more protein when actually you’re not.
Grams of protein per 100g effectively tells you the percentage of protein, so for example, a protein that delivers 80g protein per 100g is an 80% protein. So when considering your protein, ask yourself ‘how many grams of protein is there per 100g serving’…the higher that number, the more dense the protein is. HOWEVER…this does NOT mean the protein is the best for your body either, this is because a soy protein could be 90g protein per 100g but still not be as good at replenishing muscle as a protein that delivers 70g of whey protein per 100g and no soy protein. Soy protein is amino acid limiting which means it may not be as effective as good ol' whey.
Told you it wasn't straight forward, but hopefully this sheds a little light for you.