here is a link to show you how much fondant, go down 1/2 way
http://www.baking911.com/decorating/cakes_fondantrolled_tips.htm
or
http://www.wilton.com/wedding/makecake/fondant/fondantamounts.cfm
I like this site. The amounts you'll need to use and how much you need for the finished product are listed.
I think 1 recipe of MMF is about 2 pounds.
http://www.earlenescakes.com/Fondantchart.html
I jumped in on this question once a few months back this is what we were told then.
http://forum.cakecentral.com/modules.php?name=Forums&file=viewtopic&p=3276173
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