I think there is a certain amount of risk even with allegedly reef-safe butterflies. I've heard of people have good results with longnose, but I've never tried it. As for henis, make sure you get the right species...and this is easier said than done. H. diphreutes is what you want, but H. acuminatus looks virtually identical. Search and you'll find many discussions about how to differentiate between them, including comparison images.
jds