Label Sizes - Label Printer

Hi,

Quick question with regards label sizes (have searched on here but cannot find an answer). Sell FBM at the minute, but looking at doing some test shipments for FBA.

In the options there’s options to pick 27 labels per sheet etc.

I have a Dymo label printer and loads of 54mmx25mm labels which use for selling elsewhere. Could I use these for printing the FNSKU barcodes? Or is it best to buy the A4 labels and print them on the inkjet printer?

Thanks