I use locktite superglue gel on mushrooms and rics and works just fine. just make sure that the bottom of the coral and the LR is dry and they stick just peacy. I have even used superglue with xenia
I've heard of some people using super glue or epoxy to "glue" the stonie frags to ridgid air tubing or vinyl bolts. That way you can stick them in holes and crevices in the LR and move them to another spot later. I think there is a video of this on reefvideos.com.