You want to found as many as you can an dcapture as many as you can. do not worry about corruption. If they are corrupt let them do something useful and add to your support.
They can make workers, bombardment units and eventually specialist, think beakerheads. The more land you control the less there is for the AI.
You should not have city limit issues on a huge map (160x160, even with max civs. If you move up to 31 civs on 250x250, then you will have city limit issues. On that size you should get to 300-400 cities, depending on the victory conditions.