Hello,
I have literally the same type of mod (RitnLobby), except that you handle Space-Age and I don't.

I'm bringing up an issue that players will encounter very quickly: the enemies!
Is the “enemy” strength the same for everyone? If so, the difficulty will increase starting with the very first team.
Then, if a new team is created two hours later, they’ll face enemies at the two-hour progression level right from the start.

For my part, I handled this by setting the “enemy” strength equal to the “player” strength.
Maybe my mod, RitnEnemy, will help you understand the concept, if that’s helpful.

Thanks for sharing, I will check out RitnLobby sometime. I also don't have the Space Age compatibility yet, its buggy. But I plan to complete it within next month.