I'm still following the topic
I'll try your suggestions (beginning with the first; the eBook i'm working on has plenty of long paragraphs and it would take some time to indentify and test them all by adding a new class to them). Still, it is a shame that i have to create a different file specifically for Kobo users, in order to solve an issue that shouldn't happen in the first place.
Edit: And, of course, thanks for the help.