@sampsa I'm Curious why you chose to stay on 4 cities all the way up to T84. Your method seems to optimize for research, but now that you've reached your tech goal for the time being you seem to be hurting for hammers a little bit (and the rice/cow spot as well as the southern wheat would both be very productive sites). You can certainly make it work using the whip, but it definitely hurts to whip off all of the nice cottages you've developed and it might be better to generate some production from satellite cities that don't have as many juicy cottages to work.
@Undefeatable Uh... IMO Sub T250 space is definitely possible here. Top tier leader, very nice start, emperor difficulty... the advantages go on.
I think elephants should be fine and, hammer for hammer, are probably the most efficient non-UU in the game. Just be sure to not commit too many to any single civilization, and don't be afraid to conquer 2 civs at once since the emperor AI is quite slow to militarize.
As for knights: knights aren't particularly easier to reach than, say, cuirassier, because your 2 GE (which are rather difficult to generate and polluted) could easily be the GS that get you up to Lib->MT. And as compared to attacking with elephants, knights are only a little stronger but run the risk of the AI reaching longbows, castles, pikemen, and just generally militarizing more. Plus the later attack date makes it harder for you to recover quickly and might push back dates for communism and assembly line.
One more tip I can give is not to be
too ambitious with landgrabbing. You don't have to go all the way to the domination limit if doing so requires 50 additional units. Conquer when it is an easy way to expand your economy, but when other easy ways become available (GP spam, workshopping, factories/plants, building research, manipulating AI to do research for you), consider those as options as well. Cuirs/Cannons are the absolute last time I would even consider warfare, and even then seems kind of marginal.
Maybe this is some motivation to pick up my playthrough again and try to get through the conquest phase at least.