Both! I don't have any specific rules in mind, I'm just trying to push the limits of peaceful teching with a relatively small number of cities.I don't understand, then. Is the goal to see how fast you can win with under an X amount of cities, or how few cities it takes to win? If it's the former, then fair - I'll give it a shot limiting myself to 8, same as you. If it's the latter, then you can pretty easily make it on immortal with just one, even without OCC on, I think.
I'm sure someone with better micro than me can do it a bit faster with 8 cities, but I don't think you could do it a whole lot faster, unless somehow the AIs develop faster and trades you a bunch of techs. I would also be interested in seeing how you do it with just one city and no OCC, without using wars to cripple all the AIs.