Too bad only the super-Godlike-awesome Magus you fight outside of your party (in 600 A.D. and then, possibly, in 12000 A.D.) has those barriers. Also, Crono would probably qualify as a Boss monsters in this fight (just as would Magus, although they'd both still be just how they are in your party), so Black Hole wouldn't work. Just something I'd like to point out, even though I still think Magus would win, because he could also use Magic Wall to reduce Luminaire's damage.