Has anyone else found the time for the props to stop, pretty long? From my experience it should only take several seconds.

I think it is a bit too long also. I have flown in King Airs and propeller spin down does seem to be quite a bit shorter on the real thing.

I just figured this out, since to get full feather you need to do CTRL + F2. Make sure you do that when shutting down the engines and you will get the correct times.