Oracle: The priest GPP is nasty. In my test games, I usually went for Aesthetics with Oracle, since it is on the road to the Great Library. I would say that Caste System is not very impressive right now, since we can run 2 scientists with a library anyway and do not have much more excess food/population/happiness at the moment anyway. In my low-level practice games, I found a second worker useful. Especially in the chopping phase that we are reaching now. I would say that a workers is definitely better than a barracks. Worker should be pretty fast at size 4 with several good tiles at our disposal.