100 is way too hot. Not sure about KSB as I don't own any but I know my BP girl actually prefers her 78 cool side over her 90 warm side unless she has eaten. My boas are the same. Everyone seems to like it around 80 unless they eat, then they sit in the 90 side for a couple days. The only one who likes it 100 is my beardie. If your ambient is 80, I would just run a UTH on a Herpstat or VE and set it for 90. That would give your BPs a hot spot but not raise the ambient temp.

I'm surprised your snakes aren't sitting in their water bowls at 100 ambient. Last summer my sunglow would curl up in her bowl cause she was small enough. My 6' Colombian girl would just put her head and neck in the bowl to try and cool off and my BP just sat on the cool end outside the hide lol. And the ambient in the room was high 80s or low 90s, cant remember now but it was hot. And you want to be careful, too hot and you can cause neurological problems in your snake like corkscrewing and stuff which might or might not go away when you cool them.