Just want to say that I agree with the 800 = victory target, and in general I find that a good target is twice as much as you need to win a silver (which I guess is what your civ's share should be?) The 2x rule applies to all the world projects, though 2.2x is maybe twice as safe. (Like, I'd guess 700 would win it 70% of the time, and 800 would win at least 85% of the time, if not more.)