I just gave this a go, I got off to a good start and secured the Range6 planet Zoctan fairly easily by making a bee-line for range 6 tech. (Although once it hit I had enough tech to make extra-fuel tank ships anyway.)
That put me in range of the humans and psilons, who I traded some tecs with and started trading.
Not long after a vote came, with me vs the humans. The psilons abstained and silicoids voted for humans, which meant I could vote for the humans and still have them not win for a good relations boost.
I got toxic base tech and settled the 2 inferno worlds nearby, with the silicoids getting to the radiated one.
At this point my adventure took an unfortunate RNG turn, as I got the Psilons to attack the humans, and sent my attacking fleet of a Huge auto-repai to siege the human worlds. I broke the human-silicoid alliance with a lucky tech steal framing.
All looked to be going perfectly as the silicoids joined in the war agains the humans, until I got the diplo event, with the psilons.
They declare war and take Zoctan, cutting my huge ship off from supply lines which means I then loose all my transports en-route.
They then bomb my infernos and cut me off from the other two races.
Run-away psilons from here, and nothing I could do about anything.
Stupid RNG!
