Kobo Sage - Best settings for Manga

[Scorptek]

Hello, I have asked for advice previously and finally was able to purchase my Kobo Sage. So far I have been enjoying it a lot!

Most of my manga is from Humble Bundle, Fanatical and that sort of thing so I have good quality files for sideloading. Can I make them "better" by using calibre with Kobo settings or zipping them and turning into CBZ is just fine (they are oftene cbz already but also pdf and epub I think) I want them to be as crisp as possible.

I have also read a novel in epub and found out that Sage shows only half of the picture or a full one but very very small. I have disabled footer and header thing and it made it a little bit better.

I would greatly appreciate the help in finding best options or settings I could do both with my device and calibre or other converter.