Good decision on the CMS. You'll love it. Be sure to use it to give your product pages relevant URLs, Titles, and other good on-page SEO attributes. This will very much increase their likelihood of getting picked up. Also, if it has canonicalization features built in, these are often good for e-commerce sites. You'll have a lot of dynamically generated duplicate content across categories.
My advice to you would be to build your site to give your user's the best possible experience first, then worry about search engine rankings second.
Think to yourself - "If I were a user on this site, would additional content on what this page is about be helpful on this page?" If Yes, go ahead and do it. If No, you might want to leave it out.
If it were me, I don't know how much useful content you can put on a category page alone. It might even be distracting. At this point your goal is to get your users to clickthrough to the next step in the buying process. This usually doesn't mean reading something. It usually means clicking a picture or link, right? I might just leave that one alone, but that's totally your call. It depends on the situation.
Keep in mind that the further down in your hierarchy you put your product pages the lesser their importance is in the eyes of Google.
For example, if I have a tennis racket I am selling, the second of the examples below is going to appear more important, because it is closer to my root domain. The flatter you can make your site architecture while still providing a good user experience, the better results you are likely to see in the search engines.
example.com/products/sports/tennis/tennisracket.html
vs.
example.com/tennis/tennisracket.html
Hope this helps get your wheels turning.