RAnt XL was produced in conjunction with a rather knowledgeable and competent CAA examiner.
It focuses from what I can remember on the instruments and there interpretation in relation to each other.
It doesn't teach hand feet stuff more higher processing skills.
IR flying is a series of habits and trained reflexes and is very procedural to begin with ie each flight will follow the same flow.
It takes many hundreds of hours before you can make it up on the hoof, and to be honest some pilots never obtain the capacity to do that.
If you get yours self bad habits or have a different flow to that of the school you have to unlearn what you have already taken in and then get retrained. Which is why most instructors prefer a blank sheet of paper to work with. They also then are 100% certain that the foundations have been covered.
Even after 4000 hours of Manual IR flying I am still learning everyday I go up. And its not uncommon for me to have to give myself a
after flight for something stupid I have done.
IR is actually a reasonably easy skill to obtain, to master it and the tactical situational awareness that goes with it is a on going battle of personal standards.
I do wonder if I jumped into a MEP and did an initial IR profile if I could pass it today. The work load single crew none auto pilot is utterly incredible.