Keep in mind that 32 empires with 1000 systems means each empire would be able to have ~31 systems to its self, which seems like a nice robust number. After all if it was 100 empires in 1000 stars, you'd be bottled in before you could even really start expanding and exploring. I think it's a good number, and as the theme goes it can probably be modded to have 1000 empires for 1000 stars.
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