Hi Bocha,
I have a similar situation trying to make my own book files convertible to as many ereader formats as possible; also working on a MacBook Pro. You might find some of the posts on the thread I started helpful.
https://www.mobileread.com/forums/sho...07#post1164807
I'm still sorting out the information myself. As I find out more I'll redirect you to the above or reply again here. Please let me know what you figure out, too. Good luck!