Yeah I was looking at more of CxxC as well.
Don't forget, 'CxxC' can encompass a range of inter-town distances (for corruption purposes) from 3 (NE, SE, SW, NW) to 4.5 (N,E,S,W). If towns are placed at corruption distance 4-4.5, tile-assignments can usually be made such that each town can work 12 tiles with minimal to no interference, and a few towns being at CxC diagonally (corruption distance = 3) is also usually OK, so long as those 'crowded' towns have lower overlap with other towns, elsewhere in their BFCs.
In my dotmap, by virtue of being Coastal, NewCity8 has access to 5 exclusive tiles (2 Forest, 3 Coast) that no other city can use; and NewCity7 has
9 such tiles (1 Hill, 6 Coast, 2 Sea). They overlap by 7 tiles (3 of which are also shared with T'heim), but NewCity7 only needs 3 of those 7, giving NewCity8 at least 1 more 'semi-exclusive' tile (i.e. all tiles worked at Pop6),
even if T'heim were to get all the others (which it won't, because in addition to its 3x3 radius = 8 tiles, it also has access to multiple other tiles to the south and west). And NewCity8 could also take its pick of most of the tiles to the north and east, because the Wheat City will likely need a Courthouse and a Granary before it will be ready to spit out Settlers on a regular basis, and it will need a Duct and a Harbour to reach Pop12 (which likely won't happen until the mid-game).
That extra city on coast though, I was thinking 1 in, but I see that you want mostly coastal cities
As a general rule, cities should either be coastal, or
at least 2 tiles inland from the coast. Founding 1 tile away from the coast means you'll end up with 'unimprovable' water-tiles in that town's BFC, because you won't be able to build 'coastal-town only' buildings to increase tile-output. This is particularly wasteful of tile-potential with respect to Harbours, which ensure that 'fishermen' no longer require subsidy from food-rich (land) tile(s) in order to maintain town-growth at +2FPT (or better).
Building 1 tile away from the coast is also especially inadvisable when playing a SEA-Civ, because (1) all coastal buildings (including Commercial Docks and Offshore Rigs,
if the game goes that far) are half-price, so can be completed quickly after the relevant tech is discovered, and (2) you also miss out on the Coastal-town commerce bonus. But of course, (like much else) the AI doesn't understand this...
On this dotmap, moving 'NewCity8' 2 tiles inland would have impinged to a much greater extent on Trondheim and 'NewCity2', which can both get to Pop12 without a 'Duct, so shouldn't be cramped (I'd also like to place a 3rd river-town ~3WNW of 'NewCity2', in the currently fogged area); and also on the Wheat town. That's why I placed as I did
(
EDIT: Moving NewCity8 1SW might also be a possibility, despite the resulting increase in BFC-overlap with NewCity7).
) Even a library can be squeezed in sometime, without messing up the settler-cycle!
)
