Is there any info/help available on what the values in the MapSetupDefs.xml actually mean?
By that I mean how they actually affect the map generating algorithm. Obviously the parameter name refers to the object it targets, and most values seem to be probabilities which is confirmed by getting less stuff towards 0 and more stuff towards 1 but nothing noticeable above 1. So, yes, I *did* experiment. 
Specifically, what I'm after is "if I set this probability value to P, I get more or less about ~X amount of these things". The map size affects the amount (duh), so I'm guessing the map generating algorithm goes "through the map putting stuff into it" giving you naturally more stuff with more hexes.
This started as an idea to "stretch the map". I wanted to have a huge map but that would still have star systems and other stuff as if it were a medium map. Essentially, I'd have rescaled the map so that a hex would represent a smaller distance. Everything would be further away from everything else in terms of hexes and traveling time but it would still be a medium map in terms of available systems and resources. By guessing and trying out I can get galaxies that at least look like they have the number of stars about right, but it's a pain to count them from the minimap and as it's a random process you need to do it a few times to get an average, and this is just the number of stars... 
Any better way of doing this? The actual distribution algorithm formula would be nice but any help or suggestions is appreciated.