Submit the articles to sites that are crawled frequently - ezinearticles.com, top7business.com, articlealley.com, vkhowto.com ... there are a lot out there
Wellll, if your are submitting to article directories, they WILL be duplicated. That's the whole purpose of submitting to an article directory,- To get others to post the article on their site with your links attached.
Since I did the article submissions I've since learned that too many links too fast will certainly be picked up in the algorithms. Whether they hurt or not will depend on all sorts of other factors.
Is it wise (for SEO purposes only) to have three seperate links leading back to your site from the resource box? I would assume you would want to use three different sets of anchor text leading to three seperate landing pages. What do you think?
I think it's fine. I typically include 3 different links to 3 different websites. If you're going to put 3 different links to the same site, I would recommend deep-linking at least 2 of them.