I would suggest BrazilCIV, due to the requirements of Wonder(Wembley, Hoover Dam and Christ the Redeemer) for UHV2, as it would serve as a good thermometer to evaluate the technology transition that the game takes at the end of the industrial era and the beginning of the modern era.
so it would be useful for the purpose of balancing tech costs in this part of the game.
in addition to allowing you to follow, in parallel, how the USA is developing, that EnglandCIV and Holland CIV are sometimes very OP in the tech tree and check the dates and speeds at which the wonders of this part of the game are "captured" by the AI.