MultiBeast v9.2.1 for Sierra will not work on an APFS formatted drive...yet. We're working on the Uni/Multi- Beasts for High Sierra as I post this. We'll have new guides for the early adaptors when the HS release is announced. However, an olde coaches saying is, "Don't rush to fail!" So, unless your masochistic, I'd wait for the HS announcement dust to settle.