Thanks for the recommendation.
I think I will use the HD600’s for a few months then give them to my wife. We bought both pairs of the Sony’ at the same time so hers are probably about as worn out as mine.
I will then order the HiFiMan - HE-500’s and try them out. Which ever one I like best will be mine and she can have the other pair. She doesn’t really care about this as much as I do and will never know the difference.
I assume the soundcard in the computer is adequate for what we are doing.