As I mentioned earlier, if you are going for a crestie, than the temp range is between 65f~80f, you want it around 65f~70f at night, and around 75f~80f max during the day, this should be the temp of your room/flat/house, anyway, unless you live in a fridge
So no extra heating is required, however, if you do live in a fridge, and the temps strugle to get above 70f in the day, then an approprate size ceramic heater, caged and stated will do the job. the only lights you want on during the day is the uv tube.
P.S. you can put the ceramic on the roof, or on the side about 3/4 the way up from the floor, make sure the stat probe is close enough to the ceramic as to keep it from running too hot, if it does run hot and the guard gets too hot, you may have to get some perferated metal sheeting and make a bigger guard. But to be honest, I dont think it would be nessecery. However, you should have the viv up and running for a while to check that all is good befor you put the animal in