please guys, no inflammatory or "i told you so" posts...
i myself just tried the combo, 2 7" leopoldis with my gars. more than anything they stressed the crap out of the rays forcing me to add a divider to the tank. it could probably work IF the rays were much bigger
to xander, you tried rays with ur cubans right? but not any of the gators uv had correct? cubans are a different animal than gators. gators are in a league of thier own. People have had rays with gars and no problems, then some like madding had them kill the ray. i believe that one of the other mods had the ray attack and try(and fail) to eat his gar. Its a combo that can work IMO but not with gators, just as the OP has found out. In fact i believe he is still having issues with the ray, and it might pass still.