batch fit print margins to page

Hi everybody,
love LibreOffice and use it almost everyday :slight_smile:
Little question,
I happen to have a large file folder with lots of .xlsx generated files that I normally convert to pdf easily with unoconv or ssconvert.
Unfortunately those xls have “wrong” automatic page breaks and the resulting pdf is unreadable, as I want them to fit in one page (or at least fit page width).
Fixing the print area “manually” for each file (page properties–>fit to page) is of course a possible solution but it will take very long time since I have lots of files.
Is there a batch solution to format page breaks to fit page for every file (like from bash script)?
Otherwise is this possible using a template for import?
Also, may selecting the print area for every file work ? [using -selection for export in unoconv]
Im not very good at css and templates… -_-