Belly heat has been used for a long time with good results. People have also used back heat and some swear by that as well. Generally as a reptile keeper you find what works and go with it.
I have been seriously looking into the radiant heat panels and the possible benifits that could be gained by the person keeping a couple ball pythons as pets. (Way to expensive for your average breeder to consider using on all their snakes) I have made the blueprints for a display type enclosure that I want to build two of and use a radiant heat panel in one and UTH type belly heat in the other. See how the actual enclosures balance out with heat gradiants and monitor both for a while to make sure they are both safe for the snakes. Then I plan on using two normal babies of the same sex from one of our clutches that are approximately the same weight. I will try to keep everything else the same and see if either set up gives the snake any advantage over the first year or so and repeat a couple times. If I produce any repeatable results it may be worth further investigation. I may even try it with breeders at some point, see if it increases locks, egg count, egg size, or changes feeding habits or anything for that matter, but when you have limited budgets you have to start some place and the babies seem like a good enough place. All and all it still has to wait as I have a couple more racks for the snake room to build, couple more racks for the rodent room that need built and plumbed, need to actually start having snakes ovy and lay eggs, and we are currently looking at buying a bigger house.
I would love to be informed of your hypothesis, experiment design, variables and outcomes. I think this is a very worthy experiment and have my own hunch. It is cool that you are willing to do this over time.
~~McKinsey~~
"Men have forgotten this truth," said the fox. "But you must not forget it. You become responsible, forever, for what you have tamed."
~The Little Prince; Antoine de Saint Exupery