My objective is to have 1.5x his fleet size to attack him.
Good idea.
Plus, he's building attack fleets. He sent 20 cruisers a few turns ago to attack one of my planets; he just launched 40 frigates from Pi Circax, my target. It seems to me his strategy is to repeatedly attack my outlying planets in the hope of distracting me from producing a large attack fleet. I'm gambling that I can shift resources around enough that I can hit him with a huge attack fleet before he is able to beat my main attack.
Attack fleets are a waste of money against planetary defence. You should ignore anything outside its range, and why you would colonise outside it baffles me.
I've considered that. However, I think he actually might not do it. His planet has fairly low population, thus low GDP. He's already got a major disadvantage in terms of productive output on that front, I think he may not want to sacrifice the resources needed to build fleets.
You're wrong, the planet has 11 million and will hit full population in less than a week. It's certainly not stopping you is it.
If he gets PD, it's easier for me to overwhelm him with numbers of ships.
The force multiplier for PD on a direct planet assault is something like 2.5, it will definitely not make things easier.
Plus, now that my fleets are withdrawing, he may be wondering if I'm going to attack his other planet.
Cool.
SPeaking of: do we know the garrison on his other planet?
Send 1 blackbird there and it will stay alive for ages.
Right planet: 113 cruisers, 40 frigates aimed right.
Centre planet: 140 ish cruisers last time I saw it, the blackbird died.
Left planet: probably about 100 cruisers, blackbird en route.
