Hi! It's good news to hear that Bender is friendly and has an appetite.
You're doing most of the things that help keep humidity up already. Ideally, if you can keep it at 60-70%, you'd be on a roll. Keep misting, make sure the water bowl is full/a decent size, and you might want to consider a lower wattage heat lamp so that the moisture isn't completely sucked up by it.
You don't really want the substrate to be moist, since yes, it does increase risk of scale rot and bacteria. You might want to try creating a humid hide.
What are the temps? Temperature also plays a role in the shed process.