Elaine, there is also the simple method of making a dark mousse, then dividing it
into three bowls. Add 1/3 C heavy cream to one, 2/3 C heavy cream to the next and 1 cup of heavy cream to the last.
So now you have dark, medium and light mousse.
Then layer each over a cake base for a layered effect without as much work.
Chill between each layer to make your life simpler