Well, first off I'm going to say what many here will: a 55g tank is way too tall and a bit too big for any but an adult female BP.

That said, you should make sure you have the screen top treated with either foil or thick plastic to hold in heat and humidity.
Lamps can be used for ambient temp boosts, and the best bulbs IMO are the moonlight blue since red gets hotter and brighter and black turns the whole room purple...but make sure the lamp is raised at least 8-12" above the top of the tank and that you're using no more than a 60w bulb. Any higher and you'll be baking the moisture right out.
Try to locate the lamp centrally, but a bit closer to the warm side to preserve the gradient.