doing this for 3 days on the trot is quite enough
Personaly, I always find the first early the hardest, then become at least partially acclimatised. Under the previous system you'd do your 3 earlies, then 3 lates, three off, then start all over again, so you'd do a "First early" every nine days.
Now, after that dreaded alarm on the first day, you don't do a "first early" for another 17 days.
Personaly I am finding the new system less fatiguing, and am enjoying having regual four day breaks.