I dont really rush to bronze working but slavery is indeed powerful...
So what is the optimum city numbers in standard maps and how quickly I need to get them?
BTW MrCynical I read your article about The power of sushi and it is indeed a great article...
This is one of your faults.
1. start with worker (yes there are a few exceptions where warrior or workboat are better but they are rare).
2. First research the food techs needed for the resources in your capitals fat cross and let your worker work these.
3. Research bronze working , chop forest and whip population a lot.
Slavery is VERY powerful, while a large city is better for economy, you regain pop faster the fewer pop you have.
However it's often best not to whip below the amount of food resources in the fat cross.
Whip as much as you can until you have 6-8 cities.
If you have a close neighbour you can easily build barracks (for city raider promotion) and 6-9 axemen (with copper) or chariots (with horses) to wipe him out. Below noble less will probably do.
Edit:
Forgot one question.
Often 6-8 cities are a good amount until you get techs for economy.
Currency is good, extra gold w/o buildings.
Code of laws is decent, lower cost per city where you build courthouse.
Sailing is not to be shunned, if you build coastal cities you wont need to connect them with roads for trade routes.
Civils Service will allow you to run Beurocracy wich will give you +50% income from capital.
With these you can continue to spam a lot of cities, the optimal amount is ALL cities.