Well I can see I've stirred a hornet's nest with this mention of Standard Ebooks in relation to kepubs...
Anyway, now that I'm optimising, processing and converting various files, a supplementary question occurred to me.
What file format do folk advise for reading manga on an older model Kobo (Touch, Mini) - cbz? Or kepub? I've read above that kepub gives the key advantage of double tap to zoom images, which would be very handy (especially on the Mini). Is zoom still unsupported for cbz, or have Kobo implemented tap to zoom for cbz in recent firmware updates?
Just thought I'd best ask before I go loading a bunch of stuff in the "wrong" format onto devices...