Based on the discussion in various other threads I'd like to present a new dot map for discussion (sorry for pic recycling).
I inserted some ICS-towns in corrupt areas for a deeper analysis.
Here's the new towns (order of settlement), their corruption and the reasons behind them:
(note that coruption according to CA2 based on the current settlement, not regarding the other planned towns)
1. black dot - 51% - though on a BG the only good spot there immediately to settle (N loses an iPl)
2. pink dot - 54% - clears a jungle, might get extra commerce from the gems immediately
3. orange dot - 43% - saves a hill
4. grey dot - 45% - saves a hill
5. purple dot - 43% - clears a jungle
6. green dot - 43%
7. yellow dot - 49%
Be aware that every of these settlement raises corruption for all towns with currently higher corruption: (The Mariona), The Hideaway, The Nursery, The Shallows, The Greenhouse, The Whale Pont.
Every new town offers instant benefit (at least):
less unit support 2gpt
covering a coastal tile spares a unit 2gpt
base income 1gpt / 1bpt
scientist 3bpt.
production wealth 1gpt (or even more valuable: 1spt for a caravel).