Hello, I just noticed this one and no one has given you an answer. Royals aren't my specialty, but heating viv's is pretty standard. Is your glass tank an exo terra? With a mesh top? If so, you may wish to cover some of the mesh to allow better heat retention. If not, I would also cover three sides of the tank, to provide privacy as royals can be notoriously shy. A friend of mine did this with polystyrene on the base and thick brown card on the back and sides. You know the stuff, with like a corrugated inner layer? For the actual heating I would use a ceramic, 100w will do it, on a pulse proportional stat. The reason I'd pick ceramic over heatmat, is if you have a glass base to your tank, prolonged exposure to heat can crack them. Erm...thats about it really. Just make sure the ceramic is not too near the glass sides, but far enough away from the middle to provide a good temperature gradient. : victory: Hope that helps.
If its only temperary I'd put a heat mat under half of the tank and use a stat.
As has already been said cover the the two sides and the back with card or paper to make it feel more secure.
Does it have a mesh top? If it does I'd cover at least 3/4 of it to hold the heat in.
How long will it be in there for?