mk2 of every fleet ship, mk2 scouts, golems are hive and black widow, with a botnet golem on the next planet I'm taking (it has an ARS as well), and I still have a couple thousand knowledge left over. I've largely ignored starships, and my bonus ships are deflector drones (starter) and grenade launchers (ARS). I haven't found a need to unlock mk3 ships, especially since I don't have safe access to a Mk4 factory yet, and I can get a lot more utility out of 6k knowledge other ways.
That being said, I'm pretty sure I'm deadlocked and just don't know it yet, because I've just been taking every planet and the AI is reaaaaaally angry. The exo-galactic strike force (golems) are incrementing by 2% at a time, they're sending in a couple golems per wave, and it's only going to get worse. Two armored golems, black widow golem, and artillery golem in the last one IIRC. Waves are hitting the 2000 mk3 ships point, and I'm really only surviving that because of sheer dumb luck in finding a grav drill next to my home planet to fortify and abuse (120 each of basic, MLRS, laser, missile turrets, plus mk3 military, plus grav drill to slow all enemies to
and those waves are still really dicey. So, expert? More like silly, with enough experience to know better than to play the way I have been.