are you using a mix for your cake or are you doing it from scratch?
if you're wanting to do chocolate you can't really go with devil's food.
use a bread knife for cutting the shape and a pastry brush for brushing off
as far as the mousseline goes, it depends on the recipe. the recipe I have
tastes great on its own and it isn't too sweet. but if you choose you can
flavor it with just about anything, liquers, extracts, melted chocolate or
cooked and strained fruits like raspberries.