Yeah my heating cable is on all the time but its only on one part of the nest, so usually all the pupae and some of the larger larva are as close to the heating cable as possible with the eggs and smaller larva further away closer to the moisture.
As far as what i feed them its usually crickets, but i have given them wingless fruit flies as well as various other things, cooked plain chicken, peanut butter, hot dog for protein. I also gave them a bee that had stung something and was dying on my drive way which i put in the freezer then gave to them. So i might start giving them more bugs i find around my house. I've given them fruit which they always cover with trash right away, sugar water, honey diluted with a bit of water and sunburst 2-3 times a week.