The key to this crutch is that the synonym does not have to mean exactly the same thing as the original feared word.
For example, instead of saying “five hundred rand”, I have said “half a thousand”. Now in english, nobody says “half a thousand”. So it was a bit weird when I said it. But in this instance, it did actually mean the exact same thing, it was just not something most people say.
You could even say ” Come sit here on the couch, when in fact you are referring to a chair”.
As long as the other person UNDERSTANDS what you are saying, then you have used this crutch effectively. Communication is the most important aspect. I always tell my PWS, even pointing to something and letting the other person say the word for them – the questions is, did the other person understand what you said? If yes, you have avoided a stutter and COMMUNICATED EFFECTIVELY. No need to be perfect.