I am making a 4-tier wedding cake for a friend. I am not going to have time to make fondant, so I was going to buy it pre-made instead. I saw that it came in LB buckets, either 2LB, 5LB, or 20LB. I'm pretty positive I wont need 20LBs, but I'm not sure if 5LBs would be too much too. The tier sizes are 6,8,10,12. I'm pretty certain I will need the 5 LB, but I wanted to get some other opinions.

This might help: http://www.earlenescakes.com/Fondantchart.html

I don't think 5 lbs will be enough.