Yep, I signed up because of your original posting 
As preparation I’m following Traditional Base HV, except prolonging Sunday long endurance rides, every week +20km. Taking into account coming recovery and VO2 week will reach to 240km week before RA220. So far so good, seems I have found my rhythm of eating/drinking during ride, don’t need any pauses (yet at least, with last 180km trip).
Haven’t found suitable IF though: 0.7 during 6hr is doable but did not feel good, with 0.63 left too much into tank, will try 0.66 next workout.
Event itself will coincide with end of TB3 recovery week. I guess will need another recovery week after that