Building a new cage. Heating?

Place which? The second floor or the UTH? :)

I taped the UTH pads to the tile in my corn cages with foil tape, and the tile is resting on 1/4" spacers with a slit cut in the back to give circulation space.
For my BP cages, I plan to tape the UTHs to the wooden floor, then tack the vinyl flooring down over them with holes drilled in the wood floor under the pads for circulation.

I still think I'm going to do bulbs. In the end it will be a much more convenient/safe process.