Regarding minimum width of letter we ever make label of Kawasaki and Honda (Korea,Japan letter)That about 0.15 or 0.2 mm. and continuous produce it. maybe previous times we not take care this matter surely this problem for Production. For you inform 0.5 mm for graphic and 0.3 mm for label is best for us.(If less than 0.3 mm we can do but need high mesh and serious control screen and condition of Printing)But depend on design and color EX.Nagative/Positive, Color Metallic, Color 2 layer, Best Regards,Mogkol