It actually fits quite snugly around the remaining piece, so some Velcro should suit at the rear of the CF piece, and an aluminum strap will lash down the front of the carbon section.
The finish isn't perfect, as the tank section I molded wasn't perfect itself. If it were a show bike, I likely would have ensured the piece I was drawing the mold from was pristine. As it was, it was still OK. That looks like some sort of marring to the finish on the top of the tank but it is the fluorescent light reflected in the epoxy resin. I haven't polished or clearcoated it yet!