Is a very general question, difficulty to answer.
From one point of view, I think it will depend the pagerank of the websites. Is a lot better to have one link from a PR80 website than 20 links from PR.
But If you send more articles, you will have a lot more change from begging select.
I think the best way in this case is the middle solution - more than one article for several websites.
I hope I could help.