The kings all get 220 weapon proficiency in everything. You may never hit that with more than two or three weapons. The other factor is that (in Native, at least) Champion Fighters have 140 weapon proficiency in everything.
Wait for an upswing or stab, which tend to be slower (although you may have to run forward to make sure that the stab bounces to be safe). Your best bet is to prepare a sideswing, but block if they show a sideswing of their own. The way I understand it is that, in combat on equal terms, you essentially have to attack the instant their swing hits your block if they're sideswinging.
