Thanks, the defaults files eluded me.
* .sdr/* - they do not reside in the koreader dir itself
* ota/* - can be redownloaded, excluded it.
* cache/* - can be recreated, excluded it.
* data/dict/* - im still flip-flopping on this one.
* data/tessdata/* - have not looked into this yet, is it big ?
as for now its:
data_dirs="clipboard data/dict data/tessdata history screenshots settings styletweaks"
data_files="settings.reader.lua history.lua crash.log batterystat.log defaults.lua defaults.persistent.lua"