I think there are two very distinct requirements.
To pass the exam, you need the IMC Confuser.
To learn about safe IFR flight, you need an instructor who has an IR and flies for real (not many of them about).
I had the Trevor Thom book (book #5 I think) and it was poor; seemingly written by different people with disjointed bits stuck together. And almost nobody flies IFR for real using the old navaids; they are used for backup but primary nav is done with a decent GPS. I think the American IR books are much better.