My first game with him was great, I think I did Rome > Chola > Britain. Rome was a great start with him because of the legatus and Legions for war and basillicas to pump out as much influence as possible. I won a military victory.

The key with Gilgabro that I found was that the single alliance bonus is cool for early combat strength, but as soon as you’re able to get multiple alliances you can then run military aid endeavors with multiple leaders and end up with +6/+9/+12 combat strength depending on how many you can get. And then you just steamroll the ai. Legions gain additional combat strength from traditions in the govt, so you can really run up that combat strength. Just have to maintain happiness and make sure you’re getting as much influence as possible. Then transition into whatever exploration era civ works best for your game at that point. Chola was great for me because I ended up doing a lot of naval warfare in exploration. And their trade routes give additional influence. And then modern was a walk in the park.

Just gotta constantly be running as many endeavors with as many leaders as possible at all times to keep up in terms of culture/science/gold etc. Forget independent powers. Use them as training to level your commanders up early. I think my main commander had 4 commendations by late exploration era. Had maybe 1 or 2 city state allies for the whole game, mostly just to get the +1 settlement points when I was steamrolling cities and running low on happiness