I think you will find a volume 1 more useful than 2 & 3. You can't take material into the exam anyway not even a pen so anything you need is provided on the computer you will use. There were very few questions in the exam that I did anyway that used aerodrome plates (I think there were 2). I used a well expired volume 1 for study, the content still seems to remain much the same although the gnomes in WN reword, move and pretty up everything to keep themselves in a job.
What you will find useful is the rule parts available from the CAA website, parts 121, 125 etc... The AIP volumes also available here free of charge but are a bind to download due to the way they have been separated.
AIP New Zealand
Enjoy
