Fast mainhand, slow offhand. Best ratio always goes in offhand, regardless of speed.
http://wiki.project1999.com/Sionachie%27s_Partisan
http://wiki.project1999.com/Crystalline_Short_Sword
http://wiki.project1999.com/Guardians_Mace
http://wiki.project1999.com/Breath_of_Harmony
http://wiki.project1999.com/Sainy%27s_Claw
Symphonic Sabre and Harmonic Dagger are both overpriced IMO. CSS is better than either of them, and available for ~1700 plat pretty regularly.