In case it helps anyone else–
I did the conversion of cups to grams on the protein powder, since I personally measure everything in grams. The scoop that comes in the tub says its 70cc, which is .2959 cups/scoop. At 26 grams per scoop, 1-1/3 cup comes out as 117 grams for the recipe. Or 4.5 scoops, if you prefer that unit.