Don't squeeze the rockwool! It's supposedly bad for the oxygen-retaining capacity or some such. I wouldn't bother trying to dry them manually. They should dry up on their own in a few days.
I have no experience growing in just the hydroton. I've heard of people doing it but I don't know what to tell ya.
I taped the entire thing, including the bottom. Three layers of duct tape is what worked for me. Best way to check is next time you go to dump your reservoir and put in fresh water and what not, hold it up in front of your lights where you're looking inside of it. You'll see how much light is getting in. After putting the third layer of duct tape on it, the difference was (literally) like night and day.
I think it's more important to get the temperature down then to keep the humidity up, personally. You can always get some containers, put water in them, and keep them near your plants. That way the water evaporates into the air raising the humidity.
When I wanted to raise my humidity I kept a cooler full of ice water outside my grow box right next to the intake. Worked well for me.
Anyhow, good luck. I think I'm going to set my plants on fire at this point.
