Hi Jim, hope all is well with you?
I am using a #9 the fish in the picture are do-able on a #7, but only a few inches longer and you need a #12! The biggest King was not legal, probably only 65cm but with the drag on 9 on my Sage 2080 it was pulling line at will! Some of the kings in the area can go to 20kg, not much chance on a fly rod.
All the best.
Mike