KingGen hasn't been updated for A20. We've been able to generate 15k worlds with the dedi. 16k fails though.
In your game folder you can edit your serverconfig.xml to create a world size of 15360, then run the startdedicated.bat
file. It will generate the world, and after you shutdown the server, you will be able to start a new game using the
generated 15k world. World sizes need to be a multiple of 1024.