Conventional wisdom says no, but it may work surprisingly well. I tend to continually redose for many hours when I take methylone, but eventually you lose the mdma-esque properties and are left with a dirty stimulant. I have often ended up taking gram over the course of a night, but it always left me feeling cracked out.
As for safety, there's really no "safe" use of something like methylone. At this point in time we don't know very much about it, and what we do know is pieced together anecdotally.