If you want the best results possible i wouldn't use a block. Id use a dual action sander instead. that way it will make smaller, less visible scratches. Unfortunately there isn't a lot there to sand off so the advice posted about using a fine sand paper is good. Id start with 500 grit personally.
Shooting clear on it may not work out as well though since it looks like almost all of the gel coat is gone. Chances are you'll end up sanding parts of the actual carbon fiber. Priming and painting body color is a good option too.
As far as i know (and this could be partially false) most carbon fiber hoods I've ever seen don't actually come with clear coat on them. Some will come with a better quality uv protective coating than others but to my knowledge they don't actually come cleared from the factory.
*Edit... also if you choose to go with the dual action sander route use a sponge pad on it. That will help keep you from sanding too much off.
