The sim is a better teaching environment with better flexibility. You don't need FNPTII at all for initial IR. A Frasca is perfect.
A good sim requires a piston engine cockpit layout, a freeze and a slew functionality.
These functionalities are monster money saving items. A sim allows you to learn right there where you are. You make a mistake? In a real aircraft you have to continue, no way out. You have to wait for the debrief. Something went wrong on the ILS. In the real thing it's a go-around, go-back, start all over. That's not very efficient. Sometimes it leads to overloads, just doing "something" that does the trick, but not the good thing.
In the end, it's a "school", you need to learn something. In the sim... reset to a previous position and voila! Freeze, go over the mistake, do it again. You can also check if the student is really doing what he is supposed to do. Fail the VSI for the ILS, is it still stable? No? Then he's not using the AI as primary reference.
A sim is not the real thing but a procedural trainer, and the better you know the procedures, the less money you'll throw away in the more expensive real thing.
How many hours in the sim do you need? You don't know. But I'd say you need to know all instrument procedures, how to fly them, with a good time-management giving some "take a breath and relax" time.
But no, you don't learn to "fly" on a sim, not at all!
Every year I fly about 40hrs on a Frasca 142 in a very cheap arrangement. This makes my IR prof check a pretty boring flight. BUT, on the other hand, there's plenty of time left to concentrate on what's really important: "flying" and creating a safe flight.
