Well, I just killed off 20% of my army on Atlantis on Na4. I was practicing layering and stuff. I learned quite a bit. Lots of dead troops in the process. The main thing I learned was that when you are attacking a well defended target you need to do it fast and in minutes. I was attacking over a span of nearly 2 hours. Way too much time for the defender to come online and get to it. But nonetheless, a great experience as it taught me how a good defender responds to an attack.