Hello,
I have a combination of both, and i will admit i enjoy reading Jeremy Pratt's books more than Trevor Thom but in the end they both do the trick and they are both good. Read them first and then test yourself with the PPL Confuser.
There is also a book available on the internet which contains heaps of information which might be useful and it is free, it's called:
See how it flies.
Regards,
Draven