Hello again!

I feel I ask too many questions on here, but am still trying to find the perfect set up for my BP!

I have decided to switch my 2 year old BP to a glass tank after experiencing several difficulties with the plastic tub (the bottom warped and separated from the UTH even though it is regulated by a Zilla thermostat with the probe between the UTH and bottom of tub and me checking regularly with a Temp Gun). I might just be unlucky, but the plastic tub just doesn't seem to be working out and I'd rather have something sturdier and longer-lasting.

With that said, I was offered a great deal on a basically brand-new Exo Terra 36x18x18 tank (was only used for like a month before the owner switched to a rack system with more BPs).

Firstly, any tips on sterilizing a used tank? I read running it under hot water with Dawn dish soap(??) and using herp-safe tank cleaner, but has anyone ever had experience with this? I was also thinking to spray it down with MiteSpray just in case?

Next, any tips on keeping the humidity up? I am thinking to use something to cover the screen top- what material do you recommend? Plastic, cardboard, foil tape? Should I also try covering the sides of the tank with something to hold in humidity and heat? I have Foil Tape, which I was wondering would work to just completely cover the screen with a gap for her CHE?

And lastly, I want to switch substrate. I am currently using the Forrest Floor substrate (100% cypress), which I like the chunky texture off, but I've noticed it becomes extremely dry after like a week with the CHE and UTH. I was thinking a combination of like Eco Earth and Cypress? But I'm worried with the dusty Coco fiber to be accidentally inhaled or something? What's your favorite?

Recommendations would be great! Thanks all!