Easter 1916 is a good one to do though, became one of my favourites after i had to do an entire speech on it ; byzantiums are also good because the context of byzantium is the same, if you can get a grip of it
hopefully you can get access to a little green A5 size book by dr. barry spurr about the poetry of yeats - btw anyone looking for literary critics of yeats is better served in my opinion from literary critical essays from the library that you won't likely find on the internet - though having said that half of my critics for the texts came from the internet....