Hydroballs are usually placed underneath substrate divided by some sort of mesh. They are better off in terraniums, but can be used in screened enclosures. You should use live plants to help with humidity instead tho.
I know outside insects can be used as feeders, but since I've never done before I thought I'd ask first. I found this moth outside last night and wanted to make sure it was safe to feed before attempting anything.
You should get an Aquazamp or a Mistking. 10" from basking bulb seems far. How many watts is the bulb. I use a 40Watt at 7-8" from basking spot to get the temps required, but it varies from different locations you are located in.