Start low and add, nothing worse physically AND mentally than cracking 2-3 weeks into a higher volume plan because you felt like you had something to prove. Don’t look at the plans and think “yea I can commit 6 hours a week” because that doesn’t mean your body will keep up.
Last year was my first on TR, I dove into Mid volume because i had the time to commit, and 2 weeks in I was toast, stepped down to Low Volume and added Z2 rides Wednesday and Sunday and gained a ton of power.
This is my second year so I felt like I had a better base to dive right into Medium volume and so far so good!
Depends on your experience more than anything, but start with LV and add if needed