My cobalt flats have a little issue so i asked EB for a replacement but they weren't able to get me another set of cobalt flats due to them not being sold in my country, so for a replacement i asked for the Group III flats. How are these strings compared to the cobalt flats? How is their brightness and tone life? Even if they are not what i might be looking for, they are probably the best option for me as a replacement.