i've tried this method.. the problem is if you go a day and miss that nap, your whole cycle gets thrown off. Then later in the day you will probably overcompensate take a long nap because you're exhausted and just sucks. It worked well during the week then the weekend just screwed it up. I've gone to a solid 6 to 7 hours of sleep consistently with hour naps in the evening , every other day. Seems to work. Anyways .. since you are not trying to get on a cycle of little sleep, I would say 4 hours as to get rem sleep