I bought a rattle can of spray on bed liner stuff to coat the inside of my hugger. When I was at the auto parts store shopping for some, I noticed one brand had exclusions on what it could & could not be used on. As I recall, I ended up with a can of Plasti-Coat brand stuff.
It covered surprisingly well and consistent. The surface was rough fiberglass matte, and once I was finished, I was questioning why I paid good money to have the outside professionally painted, instead of just using this stuff.
If you are worried about final appearance, you could always use the inside of the lower fairing for a test surface, to see what it will look like before you use it on the outside. Just food for thought.