Domination Limit Question

[Spoonwood]

I know that MapFinder tells you the domination limit of a map. How does one estimate/know the domination limit of a map which you haven't found via MapFinder at 4000 BC or without retiring or playing the whole game out (or most of it)? Nevermind on this, you can just use MapStat on the 4000 BC save, and then take two-thirds out of the total number of tiles.

 

[Lord Emsworth]

Keep in mind that strictly speaking it is 66%.[/nitpick]