I'm making chocolate ganache to cover and fill a 10 in round and a 6 inch round I'm thinking of using 2 lbs of chocolate how much cream would I need and do you think it is enough to do both cakes? Thanksss 

Short answer, add enough cream until it's right for the type of ganache you want. I wouldn't ask right when you're baking....Also, I used the Google and came up with this thread: http://www.cakecentral.com/forum/t/746516/determining-amount-of-chocolate-cream-for-ganache

Thanks!!!