As for the infamous top 6 Forsaken - well - their positions combined great political and great physical ability, and Lews Therin himself has freely stated that Graendal's manipulative abilities are supposedly unmatched among the Forsaken, so that would surely compensate for her lesser face to face "Battle strength" among the strongest males.

She is strong enough to make the result of a contest at least contain a small element of doubt. But she would be more likely than not to lose, if the battle was against the most formiddable Forsaken channelers:

Ishamael, Demandred, Lanfear, Sammael and Rahvin.