Was thinking that well effectively with a doubled eco any fixed cost bonuses are only half as good compared to bonuses that scale per villager. E.g. free horse collar is as good as it is on arabia, but farmers work 10% faster is twice as good if you have double the farmers. Similarly getting 3 bonus villagers does not get doubled. So what bonuses really get doubled?
1. Aztecs faster farmers, same with Khmer, Poles, Slavs and Teuton cheaper farms, but all of these kinda suck on maps with fishing ships as fishing ships are better than farms.
2. Bengalis extra vills for each TC is doubled as you have 2 TCs in feudal.
3. Burgundians faster bit axe and bowsaw is nice (it being cheaper doesn’t get doubled but having it one age earlier does)
4. Celts faster wood choppers
5. Hindustanis cheaper villagers
6. Civs need twice as many houses, so Huns do get double of their bonus effectively
7. Japanese bonus doubles since twice as many mining camps and such presumably, also double the fish working faster is nice
8. Mongols do take the hunt twice as fast from both TCs I guess? Same for Tatars and Britons with sheep bonuses.
So some other commenter said that this map is four lakes with 2 TCs. Well, there are only 2 viable civs on four lakes, Lithuanians and Japanese. But the Lithuanian bonus does not get doubled for 2 TCs. The Japanese bonus DOES. So by this logic, you want to find Japanese I guess, cheaper lumber camps and mining camps means more fish from both docks, saves you more in dark age than the Lithuanian bonus does with double the TCs.