If you're going to pre-read anything it should be the bigger subjects like POF, AGK, met, instruments etc. This is because these are the subjects which airlines are most likely to question you on and they are much more important subjects than air law or general navigation.
Also, bare in mind that knowledge can go against you as the 'correct' answers in some exam questions are factually wrong. Sad to say you've just got to learn the answers to quite a few.
Airlines complain that new pilots have crap tech knowledge, CAA complain to schools, schools complain to CAA that they have to spend time learning how to play this exam game, the CAA then agree with schools but then suddenly realise they don't have the money to write better questions. Rinse and repeat.
I think question banks should be banned and questions from the CAA should be scratched and they should right much better and fairer questions.
Bit of a tangent, but this is what you can expect from ATPLs.