The C1 is a micro lathe, so do not fit too large a chuck of any type, because the overhung load will over load the bearing behind the chuck, and shorten its life.
And a big chuck takes up bed space in what is already a small lathe
Also, the inertia of a large chuck chuck will call for a lot of power from the an already small motor to accelerate it up to speed.
Also with only a 150 watt motor there is not the power to handle large work in a large chuck
60 mm and 2.5″ 4 jaw chucks were available, but I would advise against going beyond 80 mm.
At least with a 4 jaw independent, one set of jaws can be reversed (Although I always use them in the same slot in the chuck body)
So it can be possible to work with one or more jaws reversed, relative to the others, if need be.
With self centering chucks, whether 3 or 4 jaw they can only be used in the same slot whether using the internal or external jaws.
It would seem likely that most UK suppliers would be prepared to ship to Finland, at a cost. ASK!
HTH
Howard