1. What do you mean by base settings? People have different preferences, so the settings can be different too. The Kindle questions should be asked in the Kindle subforum:
https://www.mobileread.com/forums/fo...play.php?f=140
You can make a new thread there and describe your issue.
2. I don't exactly understand what you mean by "producing your own ebooks". Producing from what? As in you write them yourself? If you mean buying or downloading them from somewhere and convert to a Kindle-compatible format, then the answer is Calibre:
https://calibre-ebook.com/
There is a Calibre subforum here and you can find lots of information there:
https://www.mobileread.com/forums/fo...play.php?f=166
Now if you meant something else by "producing your own ebooks", like creating them from scratch, then there are other tools for that. Calibre is a library manager and a converter.
Note that PDF is absolutely the worst format to convert to another format. The result is often a mess. Whatever you do, try not to convert your PDF files to anything else. PDF is not really an ebook format at all and is not meant for converting.
3. As to bibles, I'm afraid I have no idea. You could ask in the Reading Recommendations subforum:
https://www.mobileread.com/forums/forumdisplay.php?f=24