I've been meaning to implement something that would allow one to ask a space station how "big" it is and then use that when spawning ads on BBS and Shipmarket. But I was just thinking of asking the population of the body the station was in orbit around, and possibly taking that (population + weight * system_population).
But maybe you're talking about something different?
Yeah I'm talking about how to choose how many stations/starports to add based on the population. You're talking about the "other-end" and using that data once it's been decided upon :)
I have no idea, the code around there is not easy to follow, but try looking into "SystemBody::PopulateStage1" and see if you can figure out what it's doing :)
Unfortunately my coding experience is close to zero, so I don't think I'm going to be much help there... If the whole universe is going to be reworked soon-ish, maybe it would just be easier to use the planets radius until it's been done. You are going to have to do this again anyway after that.