When i ran my RHP, i had the probe on the cool side set to 80F just high enough off the floor that the snake couldnt sit on it or pee or poop on it. I just secured it from the outside with a piece of foil tape and let it be able to swing inside so if the snake did manage to bump it, it would just swing back into position.
Some people will put the probe on the warm side to set the basking temp but i never liked that as you had no control over the cool side which is the most important side. A snake a little cold will live. A snake that is overheated will die or have neurological problems.