Help needed to understand syncing

[MysteryMan2]

All sorted now - got Calibre Companion and Moon+ Reader working fine with Dropbox

Sorry, this is going to be basic questions and quite a lot of them, but, I am trying to get my head around what I need to do to achieve reading position syncing across 2 Android devices (Samsung Galaxy Tab and Samsung Galaxy S8)

This is what I have at the moment......

• eBook files stored on desktop PC HDD
• Calibre, run on desktop PC - used to add metadata (authors, series, etc.) and to send eBooks to Android devices
• Calibre Companion on both Android devices, with data shared with PC
• Use Calibre Companion to select book to read
• Use Cool Reader to read books
• When finished reading, I use Calibre Companion to mark as "read" and then this is synced back to Calibre on PC

A bit convoluted, but, works fine except that the reading position cannot be synchronized across the 2 Android devices.

So, I had a dabble with a couple of readers that say they synchronise (Moon+ and KOReader), but, not very successful as I am not sure where I need to store things now!

• On the PC, do I need to move the Calibre library to Dropbox?
• On the Android devices, do I need to change location of Calibre Companion library to Dropbox?
• What do I point Moon+ to for location of books/metadata/position information?
• Do I still need Calibre Companion - access series information, mark as "read"?

Any help that will assist my understanding would be most welcome as I have a feeling I am making this more complicated than I need!

It is a shame Cool Reader cannot do the syncing as I like their interface much more than others I've seen.

By the way, most of books I read are in ePub format, maybe a few in mobi