Anyway, personally I think you should consider changing the benefits.
Specialists for my Columbus was still ok, because columbus is a project that is built halfway through the game.
However, for this mod where NWs are spawned at game start, it is definitely OP if I am lucky enough that a NW actually spawn at my starting plot, and my capital gets a instant free specialist.
While people are still struggling to build a stonehenge etc, I am already generating 3 GP points per turn, plus if it is a scientist, I will be able to found religion fast, or if engineer build wonders fast etc.
Coupled with the fact that there is no additional codes to ensure NWs are not going to spawn near each other, the game is pretty much over if my capital is built next to 2 NWs