Hello again,
for the max population per planet, the "mass change" takes no effect. In the planetsize.txt you have the max population per planet set in numbers.
Another point to pay atention to:
line 66 of the settings.txt says "Population Required to Operate One Facility := 50" so either build your facilities very slow or decrease this value.
Sending 3M people to one colony with a hypothetial growthrate of 20% and it takes you 16 turns or years (not quite sure) to have the first facility running
looks like you are into a long game
have fun
Vulture-B