Seems to me it's pretty damn important that it either doesn't rain tonight or they wait until they have about a 6 hour window of no rain...if you want to see Clemens pitch.
Trying to get the game in tonight (they probably won't, but no one has ever accused MLB of being the cleanest underware in the drawer) means stops and starts. Neither Clemens or Smoltz is going to survive a rain delay (and I can't imagine damp 60's is a good thing for a gimpy hamstring).
So then, if you think Houston's bullpen is better than Atlanta's bullpen...advantage Houston.
I can't imagine though if the weather postpones the game tonight that the field is going to be ready by noon Friday.