I didn't post here during quite a long time so I will sum up quickly what happened during the last 10 days :
Day 14 to 18: I continued Everyman but I had difficulties to do the naps at the right time and to sleep during the naps.
Day 19 to 25: I was with some friends during 4 days around the new year party and it was quite difficult to stick to Everyman since they weren't doing the experiment. So after 2 days I decided to switch to a biphasic sleep (a 6h night and a 30 min nap) which is easier to organize and I have maintain it even after these holidays.
Day 26: Since the holidays were over, I decided to restart Everyman but before I did a "reboot" which mean a long night. So I slept 10 hours that night but I woke up every 3h because I think my body lost the habit of doing long nights.
Day 27: We decided with Chris to adapt a bit Everyman to make it a bit easier, so we will now do a 4h night (and not 3h) and still three 30min naps. I already did one night and 2 nap and it went pretty well since I manage to fall asleep during both of them (which was not always the case before). I will see during the next days if I manage to come back to everyman and stick to it a bit longer.
Note: I think Chris had almost the same experience in parallel (he wasn't in holiday with me) but he will explain you himself what happened to him.