Well I did what I said I would and did a 10 day block of Vo2 work gradually building the duration of the efforts from session to session before re-starting my Build block.
Yesterday I did Shortoff +1 which is 6 sets of 3 minutes at 120% FTP.
In previous years I have found my repeatable 3 minute power to be around 115%. Yesterday I completed all 6 at the full 120% so that short Vo2 intensive block seems to have worked for me.