Hi Cupcake25, I’ve covered my double barrel/extra tall cakes using a method I saw on mycakeschool.com where you wrap the cake. There are also tutorials on you tube I believe. But cake school pre-measures some freezer paper to the circumference and height of the cake, adds a couple of inches for good measure. Then she rolls out her fondant and uses the freezer paper as a template to cut the fondant. She puts thin layer or crisco on the freezer paper glossy side and sticks it to the fondant and lifts the fondant and wraps the cake and cuts the excess in the back and on the top – works great but you have to cut a separate fondant disc for the top of the cake and its kind of hard to seam the two together. another version I’ve seen, which I haven’t tried yet but will on my cake in two weeks, is to put several inches excess in height so when you wrap the cake, you fold over the excess on to the top of the cake and cut away the excess in the center top of the cake, most likely you are going to have another tier on top to cover the ugliness left by this method. I hope I explained things well. Good luck and let us know how it all turned out.