I'd have to go back and look but there was an article in Coral I believe with propagating in the ocean. They had some strung up and some on these huge mounts. IIRC this was all with elkhorn coral.
Why not? They will grow out where you fragged them from as well.
Another thing you can do is what Anthony Calfo(think it was Calfo? maybe Pro or Feldman?) doing. He was laying the frag length wise, the coral then sends branches out along the length of the coral frag.
Not sure exactly what you ar trying to accomplish But there is not a reason not to do it.