A lot of users will be a bit hesitant when it comes to things like .bat, commandline and running scripts. But, yes, all degrees of difficulty are OK in a Developers Corner.
Editing CSS files is not particularly difficult but understanding exactly what each of those widgets and CSS streams do is not yet fully understood - at least by me. So editing something can be a bit try-it-and-hope-for-the-best.
Please don't think I'm trying to criticise because I don't mean to
Uncovering things is a good start to a better understanding.
BTW, I discovered the widget called #bookCoverListTile in nickel, is the Homescreen tile labeled 'Library' for newly added books (shows one full & two partial cover thumbnails). I'm not sure there's any great point in tweaking it but I'm just sharing that it's possible.