I don't blame you for finding /admin/eventoutput difficult. The page says that the argument fields are optional, but in reality it depends on the event type. When the page says the fields are optional, what it *means* is that the page itself won't check to make sure you've entered anything in those fields before going through the event code. (Because some events don't take any arguments, some only take one, etc.)

Right now, the only way to tell what the arguments are, as far as I know, is to look at the code itself. I'll see if I can get some sort of wiki page up for that too, although as with any documentation that sort of thing can get out of date. (I actually have a bug assigned to me that will result in changing the arguments for one event in particular, so yeah.)

I'll take a think and see what can be done.

[edit: Just realised I never explained about /dev/classes. That's a page which is intended as a place to test changes to site skin CSS files. (It's not relevant for people making journal styles, I believe.) If you're making a new site skin, you can use that page to test how each element (tables, text boxes, error messages, etc) would look in the skin. The actual classes used for the elements can be found by looking at the HTML source.]