You will need the belly heat. I don't think the heating pad would do a lot on these cages. I would get the cut outs. Actually I would get both cut outs and just ask them to save and ship the actual plastic they cut out for the light holes. Then if you don't need you can put back in place. That is what I did.
I have the T11 and I need the belly heat and two lights w/ 75watt night glo bulbs, but I keep my house like 75 in the summer and the cage is by the window and ac vent.
W/ the belly heat and two lights all on t-stats and reptibark the humidity stays around 50-55% without me doing a thing
These cages are great. And just call them and tell them what you nedd and they will work it out for ya.