Hello there i'm new to the site and the hobby of snake keeping! I recently bought a PVC enclosure with only a locking glass door on the front and 2 vents on the back. The measurements of the enclosure are 24x24x12 and I plan on buying a male super pastel when the enclosure is ready! I just have some questions/concerns that I would like to resolve before I actually purchase the animal!

My first question is about heating. I purchased a strip of flex watt that measures around I'm guessing 16 inches long by 3 inches deep, I hooked this up to a zoomed rheostat and placed it under the enclosure however the temperature began to climb very quickly despite the setting on the rheostat being the lowest setting possible! I read online that I could simply raise the enclosure and this would allow for more ventilation of the heat tape and the temperatures would lower dramatically. I have done so and the temperatures went from around 104 degrees fahrenheit to roughly 94 degrees at the hottest point I can find. The hottest temperature right now is still around that 94 degree mark so I am wondering if this is too hot? This temperature is also below the substrate and I am unsure if the temp below it is important or if the temperature on top is the only one that matters!

My next issue is my heat gradient and the ambient heat temperature, The temperature on top of the substrate where the heat tape is ranges from 83-89 degrees whereas every other location in the tank ranges from 74-76 degrees... Is this much too cold for a snake to thrive? The air temperature is roughly 74.5 degrees.. How do I increase the cooler areas?

I will post pictures if it will help out with advice!