If there is a category that suits your site please only submit main URL.
If you feel a special part of your site might fit another category you are free to submit it there. But keep in mind:
* In a category there wont be a listing in subcategories of one where a listing exists
* If content not unique or considered not good enough to qualify for a second listing it will be denied,
* Please never submit more than one URL to the same category. Only one listing in a category as a rule. As you say, DMOZ does not do any spidering. In fact its a catalogue. Something people walk through and read categories. /images/icons/smile.gif