My heating method of preference is a radiant heat panel... However, you're missing more than just that.
Poor selection of choices
MH
Who the hell is Pat?
"Pattimuss doesn't run, he prances most delicately, like a beautiful but sad fairy, winged and capped, curly toed shoes on each foot, dancing on dewdrops while lazy crickets play soft music for him to keep time by...." - Wes
You need a wooden viv in order to use this but it's been great, and cheaper than ProHeat.
I use a Radiant Heat Panel and a small undertank heat pad for the warm side of the cage. RHP's are EXCELLENT for maintaing appropriate ambient temperatures. I have an Animal Plastics enclosure and the RHP mounts right to the ceiling....i'm not quite sure if you could mount one in a glass tank with a screen lid.