If it's in a bathroom and you have tiled ceilings, then the walls must be tiled all the way up too. For that I would get one of those shower curtain rods that are press fitted. One end screws outward and when its at the correct length, you force it into the opening. Hang your lights off of that and you do not have to drill holes into the tile. I don't like drilling holes into my bathroom tile either. If moisture gets in through the screw hole, it can really rot out the drywall. If you do have to drill into the tile, then yes, a ceramic/glass tile bit is what is needed.