I did 13 hours and 5 hours (38%) of Z3+ workouts. It’d be good to know how these things scale down from 24 hours to ‘mere mortal’ hours. As usual I’m guessing that’s highly individual. You’d expect the requirement for higher intensity to crank up a fair bit IMO.
Also, are we talking specifically interval TiZ or total workout duration? I used the latter metric - my actual Z3+ TiZ was actually more like 245 mins (30%ish), which seems more sensible.