Hey sorry but I'm just trying to figure this out too. Just to be clear I have a Rich Text field containing multiple paragraphs generated with the CMS. The line spacing is set and is fine but I want spacing between the paragraphs that are within the post.
When you say : "If you add a class to the rich text element you can specify how your paragraphs styles behave in just that class." it seems like the control isn't completely there, because this means you are editing the class for the whole block. What I'd like to be able to do is to define the class that relates to paragraphs within the rich text field and add a margin:bottom to it... I tried to get at it with custom code styling but couldn't work out how to target the p element specifically.
I can get the effect I want by doing what @Mike said and changing the 'all paragraphs' bottom margin, but that of course effect paragraphs elsewhere on the site.
Am I missing something?
EDIT: edited to try and make this clearer, hope it makes sense...