Chuck and I have obviously done GCAs. Do they even exist any more Chuck?
I think they have all been done away with.
There was a time when they were common, when I was flying for Mobil Oil in the late sixties, early seventies we used the GCA controller whenever the weather was at or near limits.
GCA was the best approach you could wish for when the weather was bad....they could talk you right to touch down.
On the other hand, true zero zero is pretty rare.
All it takes is one.......
...so why not be comfortable you can do it?
The Arctic can go CAVU to Zero / Zero in a very short time.....all it takes is a high wind and you have a white out.
The Sahara can go from CAVU to zero / zero in a very short time and you have a brown out.
Been there...done that...