I tried messing about with this, and having different android reading apps, even the calibre companion, but to be honest it just made a unholy mess, books stored all over the place, some apps import, some don't, differnt places for everything.
So I ended up with the reading list plugin,
Now anytime I see a book I would like to read, I pop it on the list.
then when I'm close to finishing current book, I fire up calibre reading list, export all the ones I was interested in to a temp folder, and upload them to google play books. (free storage)
https://support.google.com/googlepla...17692?hl=en-GB
When I need to read, I just fire up my tablet, and use google play to read my book - even download to device if I need to.
Simple, easy and you know where things are.