Most of the JKI questions are specific to the booklet, there are one or two questions the booklet doesn't cover (what's longer, a 747 or an A340-600...etc.)
The JKI test really is pretty basic - very little thinking and more of a memory test than anything else.
Basically, can you be bothered to read this booklet we've sent out to you, and understand the main points?
It really is not worth worrying about ... I think you need to focus on learning at least up to your experience level and beyond.
You'll also need to think about your career at CX, and whether it will suit you in the long term - some interviewers will ask. Hong Kong is NOT for everyone ...