I only play single player, and i only play Proportions....
Play with AI hard and low bonus. Then upgrade to medium bonus for the second game.
Small quadrant also helps the AI.
I'm thinking about re-starting with an small quadrant, no neutrals, AI hard, AI medium bonus, and 4 AI races
1-Drushocka
2-Krill
3-Jraenar
4-Xiati
I've heard the XiChung is the most agressive AI, but I don't like their shipset. The Amonkrie is also good, but I want to play with only 4 AI races so I don't have to scroll in the diplomacy screen.