I quote from my original post:
my goal is to pick a few topics from either New or Latest to read in a later session, without having to go through the whole list again
I guess the Unread concept doesn’t really apply to this situation. But then, how to do it?
Also, sometimes I enter (ie. start reading) a topic, but then I have to stop reading and start working 
I want to come back to the topic later, even if there are no more posts in it. I don’t know how to do this, now that I understand Unread better: the topic won’t show on my home screen (New) even if I do make it Unread.
–
Ian