I'm with
Evo on this one - the Confuser is great but is less of a help on some of the Nav exams than it is with others. I had chronic brain fade during my exam adding on wind vectors instead of taking them off and got into a real mess. I had about 5 minutes left at the end of the exam and was still panicking even though I had been taught to use the Computer and had been doing my own Nav almost since the beginning of my PPL.
Luckily I realised what I had done and quickly reworked some of the the plog and managed to scrape through.
It wasn't representative of my Nav skills such as they are but without a good working knowledge of the Computer I'd have been in deep !!!!!. Of course I shouldn't have let my brain scramble in the first place but I have suffered from examitis recently.
I'd suggest using a combination of the Thom book 4 (although it is not that easy to understand), practical Nav exercises and the Confuser.