I just moved my corn, Jo, to a bioactive substrate, (BAS) a mixture of potting soil, peat, rock. The tank is glass with a screened top.
The humidity is great in there now because a BAS needs to be watered weekly and turned. misted daily. However, the top layer of the substrate is not damp. And, I do not water again until the top 1/3 is dry, usually weekly. I can tell through the glass when to water because the substrate changes colour when dry. The moisture comes from below, and subsequently distributes it'self rather evenly throughout.
I have lights on for the plants during the day, and a night viewing light at night. These both suck moisture out of the air but being that the ground below her is moist, she seems to get what she needs.
Prior to being on the BAS, she never shed in one piece, and I also had to assist her shed a couple of times. Yesterday, Jo shed, for the first time, in one complete piece. This was her first shed after being put onto a BAS. Also, she went "bluer" then ever before in that I have never seen her eyes so cloudy. She looks shiner and I am hoping, being that she has just one lung, that the moisture keeps her feeling hydrated inside as well.
From this experience, I feel that humidity is just as important as temperature as it takes care of different needs.
I don't think we can cut any corners in the husbandry of our captives and think that anything is not "important". Books and the folks here tell us from experience that all aspects should be monitored, so I do.