Heat bulbs are fine too if you use a flat (ish), large stone or two under the bulb. They'll heat up and the leo can sit on them to absorb the heat. I find a disadvantage of heat mats are that the cool side of the viv can get pretty cold as the mat doesn't heat the rest of the space well. That'll be less of a problem if the room it's in is heated (our flat gets pretty chilly).
You also asked how to see the leos at night without a red bulb. I know of products such as LEDs which will provide a blueish light for night viewing (like this Livefood UK Ltd.
). I've not got first hand experience of them though, so can't say how good they are.