Good to hear you control the UTH...tho it should eventually be with a thermostat so you can 'set and forget' as it were.

I myself put down a layer of newsprint under the aspen in all my enclosures and it works great, not only to tell when a mess has been made, but for cleanup as well (just roll up and toss).

Remember that the whole tank should not be 85, rather you should have one end at 85 and a gradient allowing the other end to be closer to 75. Corns can do fine, as long as they have a warm side in the 80s, at temps as low as the high 60s if they must.
What I do is have one UTH on one side set to about 84, and I don't let my apartment get below 71 (in winter). It's perfect for the corns, and they love it. No extra heating or lighting required.