really? first off my room temp is right around 71 right now. i dont have any problems and never have with back heat. have you tried back heated racks?
how did you test that its more even? do you have multiple probes taking temps from every inch of tub to come up with this, but atleast you posted that you have never used back heat.
as for the last one while you might have heard that there is no proof that either is different and one could venture off and say that either way does not matter i have never had problems from either back or belly heated racks. both snakes eat the same and both poo the same. i really wish that ppl would stop posting someone elses personal choice as fact