Hey,
Other than the past few days where we've had a real dry spell, it's usually about 60% day and 80+% night, with quite a few 90+% periods, especially in summer. Fall and winter are the dryest, and it hits 50% from time to time. Right now it's extremely dry as we have easterly winds, and it's only 42% humidity. I ran an ultrasonic humidifier all day in the grow room, and will until the ocean breeze comes back.
I grow most of the heliamphora in an aquarium tank with no lid. This boosts humidity a bit. You could get more humid with a lid and water in the tank (don't sit the heliamphora in water).
It's also important that they stay relatively cool, so any sort of basement or garage would be good here near the west coast. I usually get down to the upper fifties overnight in the grow room.
Capslock