OCC has self imposed rules. The most important is not to have more than one city. Most of the time this means, never to have more than one city. Still you can play by the rule of not having more than one city of the end of any turn throughout the game. This would allow you to build an army and maybe wonders like Battlefield Medicine and Wall Street.
I would say that those cities would need to be captured or received from the AI and not built by you. That way Im sure that anyone would consider such a game as OCC.
Using other self-imposed rules as you suggest would make the game challenging for you and a nice experience I am convinced but I would not call that an OCC.
As far as I know there are no given rules for a game to be labeled OCC within the GOTM event.
I would say that those cities would need to be captured or received from the AI and not built by you. That way Im sure that anyone would consider such a game as OCC.
Using other self-imposed rules as you suggest would make the game challenging for you and a nice experience I am convinced but I would not call that an OCC.
As far as I know there are no given rules for a game to be labeled OCC within the GOTM event.