I've provided a database containing my custom setup for the Manticore system compatible with Aurora 2.1.x
This was built mostly with data found in Jayne's Intelligence Review: The Royal Manticoran Navy with some changes to the inhabitable planets made in House of Steel: The Honorverse Companion.
The database contains a Star Kingdom race on the planet Manticore, but nothing else has been done so you still have all the research and build points. There is also a Setup Race, so you can delete my Star Kingdom and make your own if you want to change the population or other racial settings. Unfortunately, I don't think you can change the date.
If you haven't used a Setup Race before, it's okay to keep it around (useful for adding NPRs or more player races as needed!) but unless you plan to do a multiple player race game involving the Solarian League, you should probably delete the Sol system before actually starting the game. Otherwise, you're likely to discover it at some point. This can be done from the System View using SM mode. Deleting the only population of the Setup Race will not have any detrimental effects. Just be careful not to accidentally delete Manticore instead.