Pretty sure ww is fixed at 4 frames in classic. So you would hit with one weapon, then 4 frames later hit with the other.
Classic WW is max frames for any weapon
Ias does not matter
Classic ww = S-tier
the question here is another: Dual sword and single sword whirlwind in diablo 2 classic (non lod) do the same hits or having two weapons duplicates hits?
So, having two one hand weapons will do double damage that having one one hand weapon with a shield?