I don't have one yet, but I like the looks of the Reptile Basics radiant heat panels (RHP). They direct infrared head down. They should last much longer than a ceramic "bulb" and IIRC, are more energy efficient. Sound more fire safe too.
I have under the tank heaters. They are good for the hot spot, but don't do anything for ambients.
I only worry about humidity when the snake is getting close to shed. You can stuff damp spagnum in a hide. I throw a damp towel over the tank screen for a bit, and offer potted moss, and an extra water dish with water and stones. The kings like to dig around and entertain themselves making a mess of both. Not sure what a ball would do with them.