So far I've won 4 games
7/7 - No expansion enabled. Standard win obviously. This was also the only game with auto-AIP progress on.
7/7 - Fallen Spire. This and the 8/8 win below used Golems Medium, Spirecraft Medium, Zenith Trader in addition to FS.
8/8 - Standard win but with Fallen Spire done through the Galactic Capital step
9/9 - Fallen Spire again. I'm going to call this "9/9 minus" though because I had Golems Easy, Alt-Champ Progress 6/10, Spirecraft Easy enabled.
I think the most salient observation I've made from these four games that went all the way to the end is that the first was the most difficult. And not because it was the first, but rather because it was vanilla. No golems, no Mk. V turrets, no champion, no Fallen Spire fleet, no modular forts except the human one, no armor boosters/inhibitors zip. Jut warheads, which I did use to great effect in the late game. By way of comparison, the last CPA wave I handled in the last game was just shy of 25,000 ships, I was regularly fighting AI fleets of 10,000 or more on their own planets, and there were carriers everywhere for the last 10 hours or so. Without the fancy toys, the fleet from the first game just gets obliterated in that kind of environment. I know the whole "sleeping giant" bit is a big selling point for this game, but I think there really should be a way to keep fleet ships relevant as something more than a mobile defense force in high-AIP games.
Personally, for my next game I'm going to no expansions, no auto-AIP, and no CSGs (I hate how the CSG network prioritizes ARS over fabs.. maybe I'm doing it wrong but I get far more use out of a fab than an ARS), and will planet-hop my way to victory. Maybe. Hopefully.