There's always someone who wants things to be scientifically correct. Often that's me... Most people don't care or notice these details... So here goes:
The sun is not smaller than the moon. At the time of the eclipse, it is about the same size (sometimes a fraction smaller, sometimes a fraction bigger) than the moon. Just watch a real eclipse movie and you'll see. When the moon moves in front of the sun, the moment the sun is completely hidden, you can see the spill of light (from the sun) around the moon. This is called the corona and is only visible at that moment.
If realism is not needed, this is an awesome effect though and a very good tutorial! I learned a lot. Tnx.