Indeed, I will adjust their size downward in v2 (there will actually be a bit of a different mechanism in place there anyway). In the meantime, you can adjust their size downward by editing Barbs.py. Find the line that spawn the city you are looking for (in this instance they are grouped together) and after it says GameTurn lower the "5" to a "2".
If you use "find" to locate "Dublin" "Cork" "Cardiff" and "Edinburgh," you find that the first instance of the city's name in the file gives the coordinates and spawn turn, don't touch that, but the second, longer line gives the order to spawn the city, to whom it belongs, the size and any resident units.
If you use "find" to locate "Dublin" "Cork" "Cardiff" and "Edinburgh," you find that the first instance of the city's name in the file gives the coordinates and spawn turn, don't touch that, but the second, longer line gives the order to spawn the city, to whom it belongs, the size and any resident units.