eple wrote:
It seems fairly easy. Stay at lvl 3 and then increase before and during important races to build up fitness, but don't start increasing intensity to early. If you become tired and lose freshness then simply lower it for a couple of weeks. Try to plan ahead by looking at the race schedule and figure out what races you want to go for.

I've only used lvl 2, 3 and 4, and my rider has had 'excellent' fitness and freshness for the important races, and I haven't had any issue with fatigue. Tiredness is approaching 50 for me, but I'm at the end of August so that makes sense. I've only had the odd week here and there at lvl 2.

eple wrote:
Won't that give you massive amounts of tiredness in the latter half of the season?

I basically did what I said above and had excellent fitness and freshness in week 2 and 3 of the Vuelta with no tiredness. Helped me finish 2nd in the GC in only my 2nd season.