You can use any of the options available to you when you come to print the page of labels. We have used several sizes in the past for FBA shipments. The only consideration was for the label to large enough to cover any existing barcode on the packaging. We mainly used the 4 x 2cm (approx), printed on A4 pages or 62mm continuous roll which was then auto cut at 2cm by the thermal printer. The other size is a big label but as long as the barcode is crisply printed, the scanners will read it