How about a strange idea (if moving them inside - the preferred fix won't work).

Since the ambient temp is 96 you really don't need a hot spot...so you could always float their tanks in water.

Take a large tub and place your snakes tank in the middle of it. Fill the larger tub with water so it comes up about 1/3 -1/2 the way up the smaller tank.

The water will act as an insulator and pull some of the warmth from the bottom of the smaller tank. Then add some levels (up) in the snakes tank and you will effectively create a temp gradient but this one will be vertical so it is warmer at the top and cooler down below.

Put a small aquarium bubbler in the water to keep it moving and the evaporation will keep the water cooler then the ambient air.

Sounds strange but I had to do this when I lived in Arizona years ago for my lizards when my mother wouldn't allow animals in the house. This how a crude radiator works.