For the purpose of keeping the recursion machine in balance, EMA works for me. Unlike you, who have built a Fighter city, mine is about being a Negotiator at this time. The quartet of GB's that power this up: Chateau-10, Himeji-10 (going to 12), LoA, St, Mark's. If I proceed to HMA, then everything in that quartet will also need scaling up to cover the increased costs of recursion.
In mid-September, I will add on Aachen, CdM, Terracota Army, Star Gazer, Truce Tower and Cape Canaveral with only one expansion being added as various buildings get swapped out to open up space. Also coming along for the ride is a Governor's Villa. Mid-October has the Virgo going in. With these additions, I can then add Fighting to Negotiating.
What makes this possible? Diamonds....LOL!
So for me it is going to be an extended stay in EMA. You could stay put like I do if you want to do recursion but if you want to be a Fighter, once you are set up to cross the era boundary and at least get a solid toehold in HMA, then go ahead! At least that is my best guess for your city's set-up.
The bad news: Once you go ahead, there is no going back. Since it will take you time to move forward, use that time to consider all the angles, pros and cons. Good luck and best wishes for whichever path you take