Hi Rustle,
The CAAFU will expect you to do an ILS to height 250' simulated assymetric (assuming a normal cat3 ILS with 200' DH and having explained to them that ACH would be 350')
You learn that way, and you're examined that way for IR.
In the perfect world everybody would learn this in a decent simulator. Problem is, it's expensive, but then so is flying a twin, and so are funerals
When flying on a moonless night over mountains or the desert in a single, or being low and slow in a twin with only one engine producing power - you are really betting on engines being as reliable as they are.
You are correct in saying that if properly handled a twin should be safe. Recurrent sim training is the only real way to ensure you can properly handle a twin, you cannot practice dangerous situations in a real light twin because they are too dangerous!! Especially if the person training only has a few more hours than the student which was very common when airlines would hire instructors with only 100 hours multi time.
If you are engine out in a twin and ceilings are low at your destination, a properly handled engine out trip to your alternate might be better airmanship.
regards