Worth pointing out that if the link is too early (within the first 30s reading time, or 150 words or so), someone following that link will count as 'view 1, read 0'. If they then return and stay for >30s, that will give you 'views 2, reads 1 = 50% read ratio for that person. And if they clicked away and didn't even stay 30s on the linked piece, you've got 0% on that story.

So best to keep them to the middle/end of the source article.