Yep, a UTH is perfectly fine. A heat mat should never get hot enough to melt plastic, it would have to get well over 200 degrees, most plastics don't even melt until 400 and some. As for other things about the set up. Get a smaller tub, don't use a gigantic tub for a young/small bp. For a '10 baby I would say a sweater box to a 28 qt tub would be fine-depending on size. I keep my hot side 92 and prefer that my cool side doesn't drop below 80, 75 at the absolute coolest. Don't let your temps go above 95 or below 70. Good luck and welcome to the site and the addiction!