You might consider a small prototype or pilot file–starting small at first, say with 20 articles?
I wonder if the Recipe collection template might be a useful starting: each category could be an article, with its research contained in that folder. I sketched some possibilities.

In the Recipe template (in the Miscellaneous section when you choose New Project), there’s also a general-level folder for Resources, which could be useful. As someone who is continually struggling to organize my research (and I have a magpie’s tendency to collect), I tend to think in overwhelming terms that ‘I must wrestle this entire mess into shape’, and the monster keeps growing …
When you open this template, Collections will be visible. For clearer focus at first, it might help to hide collections (View/Collections/Hide Collections or click the folder button above the binder).
Play with the folders and see what makes sense to you: by article title, or by topic or date?
LATER, if you decide that this small-scale organizing system works for you, you could play with Collections: you can add or drag documents there and ‘collect’ by any number of categories. If you tend toward overwhelm like I do, I’d stick with simple and small at first. Searches can be saved as Collections, by the way, and you can drag files into Collections as well (they’re like folders of aliases, as far as I understand them).
Once you’re comfortable with the organization of the binder containing the articles and their associated research, you could experiment with Keywords and other Meta-Data. My tendency is to get intrigued by all the cool possibilities, and I end up having a mess of unorganized keywords, for instance. So I guess I’m writing this for myself as much as, if it’s useful, for you.
Good luck. I’d be interested to know what you decide to do, what you decide works (and doesn’t) for you.
FWIW, I’ve never been a happy DevonThinker—I do have research materials in a DevonThink database, but something about the structure doesn’t fit with my way of thinking—maybe it’s too linear, if that makes sense. I do use it, but not comfortably (also, many of the PDFs I use are not text-capable, so DT’s textual classification system doesn’t work for these).