Just Pointing that we talking about Ambient temps in 80s not 70s... In winter time my thermostat is set on 95-105 degrees depends on temp in the room (my supper like to turn heat late) and that is temp on heat tape... and temp in rack oscillate 84 warm-78 degrees cold side... I never have any problems with my balls...
I was even advised that Building females Should be kept even colder around 82 degrees to decrease development of Slugs...
I keep Balls since 2009 never have Hot Spot in the full meaning of that world... Just keep temp gradient...
Never had sick snake either