Rogue offhand weps: high dmg or high ratio?

[godbox]

I think title is self explanatory. I heard conflicting things from people I asked in game so I will just phrase the question real quick and any feedback or debate would be welcome =)

since double attack doesn't go off every round does weapon speed (i.e. i high dmg ratio wep) really matter as much or is it better to go for something that when it lands you know it lands.

to further simplify it:
Seb croaking dirk vs green jade axe for offhand?