Can't Print Custom Gameboy covers to shadowfox's printed size

[Captain Alexander the Bat]

After countless attempts, I still can't find the sweet spot for the Epson WF-3620 it does borderless printing but when I select scale to scale it up 100% it prints from top to bottom and it's a bit large in the Custom cases and I have issues to get them in...so how I can roughly match his printed covers and have no major gaps? I've done the paper test and it still got me issues!

I use preview which does actual size printing it scales it to 101% for borderless printing which a bit large....

[Taketheword]

Use a printing software such as InfranView. It will help force your printer to cooperate.

[Captain Alexander the Bat]

Use a printing software such as InfranView. It will help force your printer to cooperate.

I don't know if it will force epson ones to print the size I want it has to be their specs for borderless or nothing