Yes, that's right--the GG has to be alone on the tile with one unit if you want all 20 XPs going to that unit.
At Deity level, the AI starts with 4 archers, 2 scouts, 1 worker, and 2 settlers. Also, its costs (units, maintenance, civics, & inflation) are 0.60 compared to the human player's, with the exception of research, where our costs are 1.30.![]()
Oh, thanks for help... It means also that if there stack of 20 units, each will get only 1 XP?

Hmmm... Nice to know... Was sure about starting bonus (these units) but not about what else...
Still - wasn't there any production bonus for AI in later game? (Why I feel I have seen somewhere)