I have had clients who use two first names.  Hezzy Marie (RIP) would be upset if someone addressed her just as Hezzy.  Since the default is for everything to be changed to capitals, you might get away with HEZZYMARIE.  On the other hand, that might make the client even angrier.  And she has probably been protesting hyphens all her life.  Ask Billie Joe Armstrong's agent, how he files?  Maybe Billie+Joe