I was trying to figure out the best way to rapidly maximise population as Riftborn. Since the cost of each population scales up with the population on system, and because you can move pops around rapidly and for no cost, I figured that stacking flat industry bonuses on a system and keeping its population as low as possible by sending pops away ASAP was the fastest way to grow.

 Then I noticed that the starting hero gets a top-tier skill that gives 80 production on system per anomaly on colonised planet, as well as a few other bonuses, and then I found a system with an anomaly or two...

http://i.imgur.com/d9nBj1t.jpg

That system has 2k production with one pop at turn 66. Seems perfect, right? But I'm still only getting one pop per turn. This is despite the fact that the fifth Riftborn you build on a system only costs about a quarter of that!

http://i.imgur.com/nUiZ2Fz.jpg

Apparently you can never produce more than one pop per turn. What this means is that all my work stacking bonuses was about 80% wasted.

Here's the Tips & Tricks part of the post:

Which means that to maximise Riftborn production:

Find a system that can reach 150 production per turn with 0 pop, or if you're too lazy to transfer population away EVERY turn, get to tier 4 modernisation and find a system that can reach 450 production per turn with 4 pop and ship 'em out five at a time.

It's still faster to have a dedicated low-pop pop production system, I think. Probably more than one once you've expanded a bit. It's just that such a system starts wasting production at a VERY low threshold. Which is a bit disappointing, but I guess you don't want to have Riftborn able to completely ignore the concept of increasing marginal population growth costs.