I have to question the point of the Synthetic Land Creator with PlanetQualityChange = 1. Yes it is spammable, but if you used it to enable all those dead tiles, they would be full of Synthetic Land Creators. So net effect: NONE, except the waste of resources to build them.
Have you tried it with PlanetQualityChange = 2? That would actually do something.
What you're missing in your calculation is the Planet Quality-ability.
In short, the Iconians TechVic-bonus nets them around 7-15 (grossly estimated...) extra tiles on all planets they have.
I got caught up in another test game - this time as Thalan. I'm not thrilled with how the Thalan plays. The reason I got into the game was that I noticed there were seven resources (including two green and three (!) red) within two grid squares of Thala. Then I found out that Thalan starbase usage is fubar until you can get Hyperion Weaponization - which is so expensive that I couldn't get it until late in 2229.
That is one of their weaknesses (initially) but it will later turn out to be an advantage. Thalans need to spend far less MP on their starbases than everyone else. The downside is that in the early game they won't be able to do lots with starbases, so simply focus on other stuff to do.
And, year 2229 is early enough. You could use the anomaly-trick to advance that but that is a somewhat mild cheat (IMO).
Oh, and there's something screwy with the Slipstreams. You have Slip3 renamed and depending on VRM, but after I traded for Slip1, Slip3 attached itself to a non-existent Slip2 in the Slipstreaming group. It might be the declaration order bug. I'll check it out shortly.
I see, if you inject an additional tagline into the Thalan's techtree.xml it will fix the bug:
[in their Slip3-iteration...]
There may be some other techs (also in other trees) that may have the same problem.
Another test where Drath just doesn't colonize well. This time they ended the rush with their four home worlds and one other not far away. I don't think that they "don't colonize" but rather that they don't have a lot of urgency about it, and the others just get there first.
One disturbing occurrence, though. Because his position was so small, I gave Drath the Barren World tech for two vacant worlds in the area. I actually scheduled, launched, and aimed a Colony ship for him. It got about half way, then disappeared. I think he purged many of his local ships, possibly because the other AIs keep giving him ships, even without a war on. But a colony ship with a good destination?
Is Drath using a unique AI?
Drath are designed to an "early-weak but late-strong" civ. The reason why they suffer initially in the colonial rush are diminished pop-growth = less economic strength.
If you gift the AI ships they will oftentimes redirect it to the nearest planet and once in orbit, from time to time, only consider to use this ship.
Generally the AI routine will only direct Colony Ships to planets if a Scout did flag a habitable planet suitable for colonization.
At some point in the game all AIs will refrain from building Colony Ships even if planets are still free. At this point they will destroy all non-military craft and try to fight it out militarily.
I've swapped the Drath's AI personality to 10 so that they can use defensive modules in their ship-designs. The conventional personality didn't do that.