Start by weighing the bowl you are going to mix the chips and milk together. When everything is mixed weigh it again then subtract the weight of the bowl and divide the remaining weight by 2. That will give you the weight of each portion. Weigh the bowl you are going to mix the blue color in then pour the right amount of the white chocolate milk into the bowl. Repeat the same process with the whipping cream. And then the same process with the finished mousse and divide by however many dessert cups you are making.