I plan on floating the baits out on balloons from shore or from piers. I need some help on how long to wait before setting the hook. And where to put the hook. Thanks 
I use a double hook rig. I put one in the nose and the other somewhere in the middle of the back depending on the legnth of the ray and the distance from first hook to the second. I wait to set my hook till Steve or Brian (goofballs I fish with) has yelled STICK EM! at least half a dozen times or more 
Usually after its taken 35-50yds or so, sometimes more if its a big bait. I use 14/0 J-hooks btw, may be different for others using different hooks.
make sure when u rig it not to kill it just put the hooks in the top layer of skin, and let him swim around suspended by a balloon... do it enough youll have good results.
Any of you guys use shark floats instead of balloons? If so, which ones?
Any of you guys use shark floats instead of balloons? If so, which ones?
I rarley use actual floats unless I'm fishing for smaller sharks. Balloons are cheaper
There's many ways to hook live rays, some spots in the middle have a solid ridge that a j hook will go in and out of easy, in the nose you'll never kill the way but if your float is stronger than the ray's skin a shark may pull your bait off, hooked in the tail is solid but the swim doesn't look as good (not that the sharks care ), those little holes behind the eyes are fairly tough pieces of skin, that spot would probably be where I would hook a Live ray. If you're really worried about a shark ripping your hooks out, hook it through a decent piece of skin on the rim then thread the hook and some leader out of that hole and put the hook in a piece of skin on the top section. May limit swim action if done one way or another.
In my opinion a shark can find a bloody dead ray much easier than a live one lol.
Just an average fisherman.
Search Youtube for Bucky Dennis on Chew on this for hooking live rays. I have used his style and it works great and only a single hook needed.