I am planning to buy a Pilot MR in Greece. One seller told me that european MRs (Metropolitan) have only M nib and the international cartridge system. Another one told me that I can order MR in F nib as they are not available at this point in his store. I am seeking the truth! I'm afraid that I will buy a F MR but the cartridges will be the Pilot's propietary ones. What's the truth about european MRs and nib sizes?