I credit the advice you've summed up here for a large part of my success in brooding three batches of chicks over the last year and a half without having any issues other than some pasty butt that was probably caused by shipping stress. I had chicks voluntarily sleeping away from the heat on 60F nights as early as 2 weeks (in a 4x8 brooder where "away from the heat" meant no influence from the lamp at all).
