I have no idea how to estimate the amount of fondant needed to cover a cake. Is there a rule of thumb? I have 3/4 of a batch of Rhonda's Ultimate MMf (which I LOVE, btw!) and I have an 8 and 6 inch round to cover. Will that be enough or is that cutting it close? I hate to make a new batch if it's not needed, but I have to color it a deep shade of blue and don't want to find out after it's too late that I don't have enough.