If one starts a Golden Age to do civics and state religion changes, and one civic change is Slavery, one definitely should whip as must as possible before switching back to Caste System.
Normally, one should avoid whipping in a Golden Age.
Some players go into negative Fpt to run as many specialists as possible for the +100% Great People per turn bonus of a Golden Age. The only plots one works to support these specialists are farms and other high food plots.
Assuming, one isn't focused on Great People generation, one probably should work plots with both Commerce and Hammers, so one gets both +1 Cpt and +1 Hpt for working each such Commerce&Hammer plot.