Well, basically as a safety valve, I put an upper cap on the save codes. So somewhere around a few hundred planets. (I figure long before then, the code would get too unwieldly to reasonably use.) Keep in mind that the 3000 planets shown would have a save code with ~60 pages of text.
That said, I have a solution in mind...
Kind of riffing off people's scripting ideas, I could allow the user to input part of their code such as [special:protodisk, radius:100, num:3000, mMin:.5, mMax:5]. And that would create a randomly generated disk of planets, say.
Long story short - no way to get that today (unless random is interested in making a program that outputs 60 pages of code

), but there will be a way to do it soon.
Edit: Well, what do you know? Random is
one step ahead of me!