my understanding is (and someone will be quick to correct me if I'm wrong and tell me to stfu and stop giving out bad info) is that your evade is calculated by a combination of your dex and quickness (dex+qui/2). Dex also factors into pierce damage, block and IIRC parry, none of which a SB has. QUI factors into your swing speed. So, dex will only help you with evade, while the same amount of qui will help your evade just as much as dex, AND will make you swing faster.
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Jaziza - Tristan, Dragon Knight;
Tricksyn - Akatsuki
Aerendar/Aziza - Tristan, retired
Solve a man's problems with violence, help him for a day.
Teach a man to solve his problems with violence, help him for a lifetime. - Belkar, OOTS