If anyone happens to come across this thread, here's a challenge. Destroy every other empire completely. It's hard, but it's possible. By the end, I kept pressing the escape key to temporarily pause the game to survey the entire situation and determine which seedlings to move.
Here's some pointers:1. Capture two "branches" initially, focus on the high-speed planets first to help growth. Growth is essentially parabolic, which means that any small edge you have in the beginning will compound later on.
2. Focuse the seedlings from the two branches to capture one end "circle"
3. Fight multiple fronts while avoiding spreading too thin.
4. Avoid fighting in the middle initially. You have a better kill ratio if you capture the planets on the periphery branches that have a lot of traffic, but low conflict.
5. Press escape to view the macro situation and use seedlings efficiently.
And here's proof:
http://postimg.org/image/bih0ivbvt/