While it's already been said, a have a few friends that play this deck and they all run 3x Annul in the SB now. Primarily to fight off that 1st turn Trinisphere, but it just so happens that they work good in other matchups, too. 3x Annul and 3x Rack and Ruin should make your matchups vs. Artifact decks much more favorable.

EDIT:
I also think that those Daze need to be Misdirections then, because you really need Misdirection in the deck. I'd swap Long for Kai in all 3, and drop a Spiketail for the Grim #4. The 4th Grim seems even more important here because you're obviously trying to optimize your burn with the Lightning Bolts, but you go against your own ideals by dropping the 4th Grim. That doesn't make much sense...
A lot of my friends lately have been SBing in 3x Mask of Memory for the Null Rods in matchups where they are dead, and it's worked amazingly well since they have good interaction with the Lavamancers in the deck. You could try that... Or even Bonesplitters, which would really ramp up the clock.