Haven't been using viewports, but I'll try that now. I'm in what I think of as early/mid game. Just hit Rennaissance. On an eternity game, but only 3000 turns in. I gave everybody 2 great engineers, a great sci and a great merch turn 1, so tech sped up through prehistory. I'm on the Gigantic earth with no presets, but I preset about 10 myself, and I'd guess there are about 300-400 cities worldwide and 20 or so civs thanks to revolutions.