How much ganache do I need to make in lieu of buttercream to cover the outsides (not torte) of a 10, 8, & 4" double layer cake? And using bittersweet choc., the correct ratio of choc to cream is 2:1 by weight...correct? This is going to be my first experience using ganache like this!

Oh, and one of the layers is strawberry. There are real berries in the cake mix, but they'll be cooked. Will it be okay to sit out? I can't refrigerate the ganache covered cake before or after fondant or it will weep, right?

Thanks for your help!

If anyone can just answer the amount of ganache ? for now...I'm ready to make it ATM but don't know how much!