A quick tip on fogbusting:
I'm not sure how many of you fellow civfanatics know about the GlobalDefines value MIN_BARBARIAN_STARTING_DISTANCE = 2 and already exploit it. It means that new barbarian units are not allowed to spawn within a 2 tile radius of ANY existing unit (including other barb units) on the map. This rule allows very efficient "fogbusting" on smaller landmasses. Here is an example (spoiler for current LHC Huayna Capac checkpoint 1):
2 Quechuas and 1 Scout are all I need to keep my lands barb-free

. It is not required to have active vision for all the tiles (the fog doesn't matter). I've changed the Dotmap-function of BUG to display the no-spawn areas for my three units.
Note that barb cities CAN appear 2 tiles away from my units if the tile is in the fog though.