Originally Posted by silverraven
So basicly I need to convert books into epubs, but they need to be different for each reader. (one reader 5", one 6") Can I do this?
The answer to your question is that you just have to create one epub file and it will work fine on both ereaders. When you buy a epub at any of the online stores, they don't ask you what size reader you have, do they? Epub is a reflowable format that will work fine on either version.
Output profile size comes into play when you are dealing with CBZ comic files and other graphic oriented formats.
In case individual image size makes any difference I would just set my Calibre for the 5inch reader and do all my conversions using that as my base. No muss no fuss one size fits all.