OK, there is a thread from Mtbaker about this, but I have no idea how to link it up to this one.

It's called "how much fondant do I need to cover a cake" That will tell you exactly how much to buy.
Chocopan is different to work with than Satin Ice or homemade. I would suggest either getting some well in advance and practicing, or mixing it with Satin Ice so that you get the yummy flavor of chocopan, but the stability of Satin Ice. I've never made my own, so I can't help ya there.

I hope that helps!
