@Bede and Jurimax: Thanks for the analysis. (@Bede: There are 2 curraghs in my save)
I would like to add a comparison of the way we handled the worker:
Jurimax: 2 cows irrigated and lux hooked up
oopsy poopsy: 1 cow irrigated, 1 cow mined, 1 bg mined, no lux
Peacemonger: cows irrigated, lux hooked, worker close to next city (which mean we can get lux and terrain improvements to the second city quickly)
Bede: Only one cow irrigated and roaded, no lux, BG and sugar is mined and roaded, no lux
dl123654: second cow is irrigated in one turn, lux hooked up.
trikos: 1 cow is about to be mined (must be stopped or irrigated later), cow irrigated and lux hooked up
We need two irrigated cows sooner or later. The worker in my save has to be changed to irrigation unless we want to let it finish and irrigate the (then) mined cow later. I think Peacemonger handled the worker best (assessed with out current plans in mind).
I think it was a mistake of me to move the worker to the lux and hooke it up and then back again to the second cow. I started mining the cow before I realized we could have three +5 food cities.
The other save I would consider playing is Jirimax's, but I suggest my own save because the settler is next to where we want to settle the next city (sorry for pointing at myself). This means two turns of production in the second city. In the long run, we will win more from this than we will loose from the worker mistakes (I think).