What to wear for English WSCA classes?

I'm showing in a couple of English pleasure classes this weekend and the show bill says WSCA rules for attire but I'm not sure what that is. Would I be able to get by with paddock boots (black), half chaps (black), and a polo shirt? I have skinny jeans that I prefer to ride in over breeches, would that work or are breeches required? I will by buying a WSCA rule book but I wouldn't have it by this weekend. Thanks in advance