So, guessing that Ankor Wat is a flat 25% decrease, after the formula, not inside the formula.
And the same would go for the Russian UB?
I was thinking of using this in conjunction with Shoshone start.... to enable a super-land grab of epic proportions. Then grabbing up all the defensive abilities you can possibly muster.
Guessing the "tiles already obtained" doesn't matter how they're obtained? i.e. initial city placement vs outright purchase with gold or culture?