That is, 66 for all female channelers. As I said elsewhere, we know there are at least 3 levels above Lanfear for men, but this info came from a file which was written after the weaker male Forsaken were dead (Rahvin, Asmodean, Sammael). We suspected when we first read this that there were 6 levels for men above Lanfear, which fits with RJ's numerology for linking. The minimum number of men needed for a circle of 72 is 6 (6 men, 66 women). Of course, most men will fall somewhere on the scale for women, but none of the files we read on the Asha'man had any detail about their relative strengths because it wasn't as important to the story.