The bulb or ceramic is your best option. UTH on the side just heats the air in your room if its not insulated as if it were on the bottom. Meaning building a wall around 3 sides of the outside so the uth iin between the glass were its stuck and the wall. And they are burrowing frogs that burrow to cool off not warm up so being on the bottom is really unnatural to them. Don't get me wrong if this is the only way to achieve your temps it is recommended in some books, but IMO this would be if it was the last option. Its better then no heat at all.