Well, I was able to chop 98 turns off my first effort despite landing on a map where the nearest mountain was on the other side of the globe. Had to fight in the end for aluminum that Rome did not know it had. The worst part was the agonizing ten turns of shipping my last space piece across my internationally popular trans-global railway- including the turn when I got sent backwards when my open borders agreement expired
. Even so I was around 340. With what I learned + a better map I'm sure I could get sub 300. I did not realize how powerful those siege towers were in the early game. If you don't worry about promotion you can capture an early city with one tower and one lesser guarding unit (just chilln there in heal mode absorbing the city's bombard)