2 QuestionsFollow

Here's the link to my armory page:

http://armory.worldofwarcraft.com/#character-sheet.xml?r=Ner%27zhul&n=Slayt

I am a lv 56 Rogue that is going to respec to sub at lv 60, and I have 2 questions real quick. First, I'm wondering if I should put some points in the Setup talent. I would assume that w/3 ranks (75%) chance to add an extra combo point would be a nice addition, but I dont see alot of Sub-Spec Rogues with this ability, why?
And second, what are the best daggers to use for Sub-Spec 56-60?[b][/b]