Cedric, I think you should be able to go directly to the Instapaper website to read it later.
I haven't used Instapaper much either (I'm only now going through Module 5), but so far I've been using Evernote only for accumulating research for new blog entries. With that said, sometimes I may not want to use certain articles in Google Reader for research for your own blog posts - but I still may want to share them if they're good pieces. So instead of adding them to Evernote, I'd just add them to Instapaper if it's a long article and I don't have time to read it at that very second.
From what I understand, the mornings are used to just browse through potential material that you can share on social media and then the evenings are used to do the actual reading, sharing, and commenting - instead of doing it all at once in the morning (and getting sidetracked).