Well, I'm through with the game

[Kristoffer O]

I think there are some criteria for national scales. This was the case in dom2 at least. There might have been unintentional changes to this. IIRC Ermor was hardcoded to have other settings than other nations and cold/heat loving nations often took the preffered scale, but with the differentiation into eras and a tripling of nations numbers this might have been screwed up, (probably not the cold/heat stuff, but possibly ermor's preferences).