Three tiered Darth Vader Cake. 10", 8", and double barrel 6". Tiers are covered in marshmallow fondant. The head is sculpted rice krispy treats covered in fondant. I iced with smoothed buttercream under the fondant, froze for 20 minutes, then covered in fondant. For the middle tier I used a tool to indent the design of the death star pattern all around and then painted with silver luster dust. Whenever I indent fondant already on the cake like this it starts to sag a bit. Any suggestions on how to reduce that would be great. Thanks for looking!