So you use a two RHP to raise the ambient temps 15+ degrees? That's what I thought. Sure they can raise the ambient temp a couple degrees, but anywhere close to enough in the OP's situation, it's not going to happen. I understand what you said, I think you don't understand how temperatures work.
I'm not targeting you, you're trying to argue what you think over logic and what actually works and doesn't work. You don't take a chance on an animals life like that. I know it's not going to work, and if the OP gets the snake anyways, then they're irresponsible. If they won't listen to facts, do you really think they're going to listen to anything you say? No, that's proven as well.
I know a guy Eric Pharr who used to free handle venomous snakes, I advised getting him getting venomous snakes. He got them anyway, hundreds of people advised him against free handling and he did it anyway. You know what made him stop? He got bit by a Cerastes vipera. When people do exactly what you advise them against even with facts, history shows they do what they want anyways. People know what's right and wrong and they break the law anyways.