Radius tang on a slipjoint is the curved section that contacts the spring when pivoted around the pin.
As opposed to halfstops that do not have a curved section.
I gottcha I call that a "cam tang" Same thing different terminology
I doubt Bret would make one , as long as I've known him,to the best of my knowledge he has not built one.
I did see one time,from him,a folding shaving type,straight razor. Man it was cool.
