Gladiator Society Mission Creation Tutorial:

For add your own GS Bounty, or add your faction on the endless battle or add your unique ship on the endless battle.
Go look on data/config/gsounty.
You will found a readme for made your own GS Bounty.

You can copy the folder on your mod for add many things! (Do not forgot to empty them before.)
Work exactly like Nexerelin faction.

For add your faction on the endless battle, just add the faction id on your own CSV EndlessFaction.csv

For add your Endless reward, same thing.