You can submit the same article to different directories. The only time duplicate content becomes an issue is when you have the same content on separate pages on your own site. For example, if you have a traditional web page and a print-version of that page, it would be considered duplicate content.
So, since there’s no duplicate content issue for submitting the same article to different, you don’t need to change them at all.
As for spinning, don’t do it. It makes your content a jumbled mess, and it lessens your credibility. If you need to rewrite things, do it manually. It will save you alot of embarrassment later.
Articles that are rewritten to cover the same topic from a different perspective may be an improvement, but if you’re going to publish spun articles you may as well publish the first drafts instead. They won’t be as polished as the final copy but at least they’ll stand a chance of not being total garbage - if you write reasonably well, that is.
My guess is that anyone that thinks a spinner can create anything remotely passable is a poor judge of literary quality.