Best way to copy the Minimal tempalte?

Hi, and thanks for this great plugin. Can you share a tip on how to copy the minimal template so the new template is exactly the same as Minimal in terms of styling. I have copied the folder completely and just renamed the folder. The system recognizes the template however when I generate an Invoice with it the margins and the whole page seems to be shifted. I have seen your answer somewhere about a setting for margins in your abstract-document.php file, however this doesn’t seem like a viable solution for me as the updates will be erased with the first plugin update, correct? Any other tip?