Hey thanks for the follow up and for pinging Ali as well, that's all great info! Helps alleviate my concerns about the heat tape on the bottom. I'll probably place the enclosure on hockey pucks anyway.
One more thought while I have you...I ordered a T8 with their included fluorescent light as well as an RHP direct from Pro Products. AP pre-drilled the mounts for the light fixture along the rear edge of the T8's lid, which incidentally places it within about 1/4" of the mounted RHP. Any concerns about those two units being so close to one another?