We started with a chocolate cake recipe we loved that calls for 1/4 teaspoon of leavening per cup of flour; we wanted something less dense and higher-rising. Shirley Corriher recommends 1 1/8 teaspoons of leavening, but that seems like too much - we're ending up with layers that have high and low spots even though we're using a collar to promote even baking. Is there a better ratio of levening to flour? Is it something else? Or are we destined to be leveling with dental floss?