Pedro -
I used to get voids and pinholes all the time on deep complex guitar shapes. They always came down to fabric being pulled way from the walls of the mold during vacuum. Sometimes it was the vacuum bag pulling, sometimes it was the release film or the breather fabric. This is why injection molding and silicon bagging material fixes these problems in production; the fabric doesn't move. My best advice is to be very careful, and work on cutting pleats in the release and breather fabrics so they don't interfere with, and pull on the CF when you first apply the vacuum. Once the vacuum is applied, poke at the trouble spots and make sure everything is seated properly; look for spongy areas.