See my posting under basic strategy for a recommended tech sequence.

I took twenty minutes to check the complete planets list for my map. The biggest systems are Sun at 46 planets plus 3 moons followed by Tessana @44 Eskirk @44 and Ixe @43. Invading those systems once they have been colonized would be a real challenge. Imagine twenty shipyards tossing out battleships as you move from world to world. Best to go in with at least a dozen dreadnoughts to visit them all in a turn or two before they can build ships.

On the other hand it occurs to me that the automatic AI empire management has probably never been tested for over 200 worlds. I tried turning on all AI on one of my games I was tired of at 600 worlds and the computer locked up. So it is possible that I have generated a monster that will just crash about turn 100 before I am ready to conquer the map. I hope not....

Let me know if I also need to post the system names file I used. I do not know if it pulls system names out of the file or has them in the map itself. They should be in the map. On second thought I will just attach it. The names I made up are all three letters because I get tired of writing long names on my plans.

If you want to make things interesting generate the game with your race Last rather than first. That way the AI gets to move new ships before you move.... I find it interesting enough being first so I can decide which sitting duck to pursue. My ships experience reaches Legendary +50% quickly....

One thing I forgot to mention is to turn off automatically claiming any system you colonize. This just makes the AI mad especially when it has a colony there. Do not claim them, just colonize them and grin...