Luckers knows his stuff. From the BWB:

 

... and finally seventy-two (six men and sixty six women). This last, a circle of seventy-two, is the maximum possible link in terms of numbers.

 

The World of Robert Jordan's The Wheel of Time, page 23

 

There are other combinations and ratios of men to women, but there must always be at least one more woman than men, except in the cases of two men and a woman, and one man and one woman. And in terms of sheer numbers, 72 is indeed the upper limit.

Thanks Robert.

Aha, that's why I got mixed up. It wasn't the number of channelers in the circle that results in imbalance, it was just the nature of the circle itself.

 

Thanks for clearing that up, I need to reread sometime.