Solves all your problems, actually printing in the center!
believe it or not, this printer (and a lot like it) need the paper held a little bit more to one side then the other :)

super easy to adjust size for all rolls and printers.

This, and similar mini thermal printer have a large 3mm gap of empty space between the roll and printer walls, that allows your roll to be loaded into the printer with no option other then totally off center, by a wide margin.

one of these adds 1.2mm of space, the other 1.8mm, totaling 3mm used together, super simple