I would definetly recommend checking out Basso's workouts at mapeisport.it. He actually does a lot of intervals that not much different than people on this forum. 3x20s, 6x6s, 15 sec sprints, etc. The big difference is those workouts are performed during a 6 hour ride, so there's a ton of L1/L2 and JRA. Lots of rides over 200 TSS.