it is possible to overload on too much unnecessary detail when researching\revising that won't actually benefit the person and that is what i was getting at. I am limited on the time i have available to read and research on this due to having a job
It's not possible to overload on too much detail. That's what they did during my Stage 2 interview, they'll find topics one by one, and go into details as far as you can answer. If you are not able to answer, they'll give you clues to help you derive the correct answer. After that's done, they'll do the same thing in another topic.
A good strategy that might help you, and I think someone else has mentioned before, is to study all the subjects covered in the JKI booklet in depth, with the aid from outside sources. But pick a subject that you will study extra detail in. During the interview, they will probably ask you which subject you liked the most from the JKI booklet. That will be the subject that they will ask you first and most likely go into most detail in. Also, if you say you like the 747-400 the most, make sure you know about that plane. They will ask you!
I would say, don't treat the JKI booklet as study material but treat it as a study guide. See each chapter of it as an introduction to what you need to know. With that, explore into those subjects.
Hope this helps!