Right, I got a good game going. I got about 12-15 systems sealed off with one entrance point, and that is heavily defended, and I got no problems holding it.
However, now that the game has been going on for a while I have discovered that the dyson golem was right next to both of level IV planets next to one of the home systems.
so its a square as follows:
I freed the dyson since it seemed like the decent thing to do, but right there and then I did not have the forces to take on those two heavily defended planets that has been reinforcing, so I retreated to find another ADR and a Mk IV factory.
To do this I got several system I have captured here and there through out the map, I have built some defences and it has held good so far.
Then I noticed the boxed in MK IV planets are starting to send Core Bombers out now and again, I assume they are overflow ships (playing against a mad bomber), in waves of 40 to 100 units. This was ok to start with, but then I had a 2800 unit CPA that overrun my outlying systems, and now whenever i just get my systems rebuilt a bomber wave or two comes to visit and I gradually loose the systems.
The systems is not all that important, as I only keep them for some resources (my truly important systems like MK IV factory is well defended, but I would like some advice on how to best protect against Core Bombers with minimal effort and micro