They all are. But note that he also doesn't think the women wouldn't be a threat. I mean, Mesaana seems to think she matches Semirhage on most counts, yet that just doesn't seem to be true based on what we see. So I give little weight to most of their personal assessments of ability.

It isn't sourced, just based on what we see in the books, and on RJ's statement that the top six were pretty stable, and included those I named.