I think flourescence is whole lot of hogwash if you are in color grades better than G. They say it has some impact on more yellow stones but I never really looked at those much.
On a side note in relation to your original request - you really do need to look at the diamonds. One thing no one seemed to mention was that the clarity stuff can be very different in the same grade. Most notably, the color of the occlusion. Two diamonds had the same GIA rating (and def get a GIA certification) but one was a (relatively) larger "feather" and the other one was a smaller black speck. The one with the feather looked way better.