I've used a variety of arrangements over the last two and a half years, or so, that I've been using a Windows tablet as my ereader. My current method is to install calibre and my main "master" library on my tablet. I like having all of my books on my tablet.
Monthly, I backup my library to my desktop computer where I also have calibre installed. New books are added to the tablet's library and basic metadata massaging is done there. I have a BT mouse and keyboard on my desk to aid in these tasks.
Occasionally, I will add a new book to the desktop library first, in order to perform a format conversion (I read ePubs, so AZW3/MOBI need conversion). I also do any editing of ePubs and AZW3 books on my desktop using calibre's Editor, though usually without adding to the library. New books are copies across the network and placed in a shared "Calibre new additions" folder on the tablet.
When running calibre on my tablet, I usually use the BT mouse and keyboard. I have the
TouchMousePointer utility installed for times when I'm out and about and don't have the mouse and keyboard. Before getting the mouse and keyboard, I used
TeamViewer to remote control my tablet from my desktop machine so that I had mouse and keyboard, plus a larger display.
I don't use calibre's ebook-viewer for reading these days, though I did for a while. I've bounced back and forth between Freda and Book Baazar Reader with Freda being my current favorite. I "Save to disk" from calibre and then load into Freda. I only keep 2-3 books in Freda, only those currently being read, and delete Freda's copy as soon as they are finished. Apps like Freda and Book Baazar Reader have to keep their copy of the books in the primary storage drive (C
, which is always a limited resource on small Win tablets (mine's 32gb). I keep my cablire library on a 64gb microSD card that is drive D:.