You won't be able to lock the system to the same number of turns per era. You would need a completely balanced number of techs as well as the amount of research points required tied to how much RP civs are producing during those eras. i.e. If the total research points for each era were 1000 (just to use an arbitrary number) and you produced 20 RP in the classical era per turn, you would complete the era in 50 turns. But if you set the Renaissance period to 50 turns, even if the RP total were again 1000, you would also have to produce at the exact same 20 RP per turn to make that 50 turn setting. Of course, in reality, the number of RP needed per era is NOT the same, and the amount of RP produced fluctuates quite a bit and will continue to as long as new buildings are introduced and tweaked. It gets more complicated when you then consider game speeds. Basically the best measure at the moment is just to play and see how long it takes to move to each era on Snail (which seems the most balanced) and then use that as the standard upon which to build the model. This is something I've been documenting for myself lately to try and address this. To be honest though, I haven't had a lot of time to play the game lately, so Praetyre if you want to adopt that baby, by all means. For my game, I reached the Ancient Age on turn 580, Classical at 841, and Medieval at 1022. I haven't gotten to Renaissance yet. This is actually playing and not auto-play, which I felt might not be the "most accurate" for how a player would progress.