I think I've completely forgotten, but where is this?

But that means nothing. Graendal would notice anyone even a little stronger than her. She has probably known only a handful of women able to exceed her, and even if none of them exceeded her by all that much, finding a newcomer with that kind of strength would shock her.

Yes, but by what metric? If the Foresaken are all clumped together, she could consider a woman at 98 much stronger than a woman at 88. Wouldn't change the fact that Moghedien isn't necessarily far from the others, given what we got from the prologue.

Again... so? Demandred and Rand were close, but differentiable. Same with Taim or Logain and Rand. Nothing says Cyndane isn't the same distance from Lanfear. Everything supports it in fact.

Shielding isn't a 100% thing anyway. Shields can be misplaced, or not take hold on one go and take hold the next. We've seen both on screen in the books. Shielding isn't the be all and end all.

The number is 50%. I seem to remember us agreeing to a 66% rule, which said that the person you shielded had to be at least weaker than 66% your strength for you to shield them effectively all the time. This is ignoring skill in shielding, of course.

I really doubt there is this huge gap between Moghedien and Mesaana that no known character fills. RJ's 21 level list has no empty levels, as far as I know.

Its more likely to be Lanfear at 100 (exactly why is she 99? RJ said the strongest woman equals the strongest man, and there's good evidence for Lanfear being the strongest woman) and Graendal at around 96, with Cyndane falling in between at around 98.